Annual Report 1955

National Bureau

of Standards

U. S. Department of Commerce

UNITED STATES DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director

Annual Report 1955

National Bureau

of Standards

Miscellaneous Publication 217

For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price 55 cents

Contents

Page

General Review 1 1.1. Introduction 1 1.2. Technical Activities 2

1.3. Administrative Activities 9

1.4. Publications 11 Research and Development Program 12

2.1. Electricity and Electronics 12 Fundamental electrical units 13, Electrochemistry 14, Improve- ments in measuring techniques 14, Resistor noise 15, Electron

tubes 15, Research on electric spark discharge 16, Pole-top

failure 16, Design of mutual inductance transducers 16, Marine weather station 16, Special electronic devices 17, Preferred circuits 17, Mechanized production of electronics 18.

2.2. Optics and Metrology 19 Intercomparison of standards 20, Determination of color dif- ferences 20, Glass color standards 21, Spectacle lenses 22, Aviation lighting 23, Refractometry of synthetic crystals 24.

2.3. Heat and Power 24 Temperature standards 25, Low-temperature research 26, Properties of air and related substances 28, Thermodynamic

properties of metals and salts 29, Mechanical degradation of polymers 29, Combustion in engines 30.

2.4. Atomic and Radiation Physics 31 Velocity of light redetermined 31, Radiation balance 32, X-ray

calorimeter 32, Electron beam extractor 33, New radiochemistry laboratory 33, Attenuation of gamma rays at oblique

incidence 34, Zone melting apparatus 35, International inter- comparison of radiation standards 36, Negative ion research 36.

2.5. Chemistry 37

Colloidal dispersions 37, Titanium compounds 38, Labeled

sugars 38, Research in analytical chemistry 39, Electrodeposition of metals from organic solutions and fused salts 40, Advances in physical chemistry 41, Evaluation of scientific data 42, Special investigations and devices 42.

iii
.6. Mechanics t . . . Measurement of hearing 44, Jet noise 44, Architectural acoustics

44, Measurement on material substances with sound 45, Analysis of sound 45, Measurement of high pressures 46,

Aerological and flight test instruments 47, Water-wave

research 47, Density current research 48, Boundary layer

transition 48, Surface roughness 49, Vibration standards for the calibration of pickups 50, Thermal stresses 51, Fatigue

strength of aircraft structures 51, Airplane design 52, One

thousand-pound balance 53, Densities of alcohol-water mixtures 54, Combustion in high-velocity air 54, Fuel accessories

for aircraft 54.

.7. Organic and Fibrous Materials

Crystallization phenomena in polymers 55, Behavior of "pure

gum" rubber vulcanizates in tension 56, Effect of atmospheric

contaminants on textiles 57, Effect of light on coated groundwood papers 57, Accelerated aging of record papers 58, Amino

acid analysis of collagen 58, Micropore structure of leather 59, Temperature of tires 60, High-temperature polymers 60, Blood plasma expanders 61, Dielectric studies 62, Multiaxial

stretching of plastic glazing material 62, Infrared spectra of

insoluble organic materials 62, Mechanism of rain erosion 63, Panographic dental X-ray machine 64, Gallium alloys 65.

.8. Metallurgy

Constitution diagrams 65, Properties and behavior ot alloys 66, Mechanisms of the deformation of metals 67, Titanium 69, Fatigue of metals 69, Corrosion 70.

.9. Mineral Products

Thermal decomposition of crystalline materials 72, Structure and properties of glass 72, Ceramic transducers 73, Ceramics

containing uranium dioxide 73, Mechanism of deformation in ceramics 74, Electrical conductance in vitreous ceramics 75, Thermochemistry of inorganic materials 75, Crystal structure of the phosphates 76, Standard X-ray diffraction patterns 76, Phase studies of the system lime-silica-water 76, High-temperature, ceramic-metal strain gages 77, Phase equilibrium

studies on portland cement 77, Effect of ceramic coatings on

the creep of alloys 78, Reaction of portland cement with car- bon dioxide 79, Refractory concrete for jet aircraft aprons 79, Properties of glass fibers 80, Special optical glasses 80.
Page

2.10. Building Technology 81 Instrumentation and measurement 82, Control of cracking in reinforced concrete 82, Flame spread test method 83, Aircraft

fire detection 84, Water usage for drinking water coolers 84, Effect of moisture on rcof deck insulation 85, Performance

of air cleaners 86, A study of a ceiling panel heating system

86, Asphalt roofing 87, Roof maintenance manual 87. 2.11. Applied Mathematics 87 Numerical analysis 88, Digital computation 89, Statistical en- gineering 91, Mathematical physics 92.

2.12. Data Processing Systems 94 SEAC 95, Analog computers 95, Development of new computers 96, Computer circuitry packaging 96, Diode amplifier

96, Cold cathode gas diodes 96, Other diode studies 97, Magnetic core investigations 97, Rotating reading head 97, Highdensity magnetic tape recording 98. 2.13. Cryogenic Engineering 99 Cryogenic equipment 99, Cryogenic processes 100, Low-temperature properties of materials 101, Liquefaction of gases

102.

2.14. Radio Propagation Physics 103 Oblique incidence studies 104, Low-frequency propagation 105, Cosmic noise 105, Arctic radio propagation 106, International Geophysical Year 106, Speed of light 107.

2.15. Radio Propagation Engineering 107 Radio noise studies and noise predictions 108, Tropospheric

forward scatter propagation 109, Phase stability of VHF and

UHF transmissions 110, Obstacle enhancement of signals

110.

2.16. Radio Standards 110 Power measurements 111, Voltage standards 111, Attenuation

standards 112, Coaxial resonance line for microwave impedance measurements 112, Precision microwave interferometer

112, Dielectric and magnetic materials 113, Microwave

spectroscopy of gases at high pressure 114, Atomic standards

of frequency and time 115, Frequency standards and standard frequency broadcasts 115.

2.17. Basic Instrumentation 117

Specific instrument developments 118, Instrument reference

service 119, Indexing system 120, Instrument surveys 121, Studies on shock and vibration 121.

V
Page

3. Calibration, Testing, and Standard Samples 122

3.1. Calibration Center 123

3.2. Making Standards Available for Practical Use 123 Time and frequency 123, Clinical thermometers 124, Dental

materials 126.

3.3. Calibration Requests Show Industry Trends 126

3.4. New Standard Samples 127

3.5. Testing for Government Purchase 128

3.6. Services in Other Areas 130

4. Cooperative Activities 132 Federal specifications 133, Methods of test 134, Industry specifications 134, Building and safety codes 135, Radiation protection 136, Weights and measures 136, Research associate program 137, Optics 139, Heat and power 140, Building tech- nology 140, Data processing 141, Radio propagation 142, Dental materials 144, Metals, mineral products, and other

materials 144, Acoustics 145, Smog 146, Highway truck weighing 146, Educational program 146, International 147.

5. Appendices 149

5.1. Organization 149

5.2. Fiscal Data on NBS Program 154

5.3. Advisory Committees 155

5.4. Awards and Honors 157

5.5. List of Publications 158

vi
1. General Review

1.1. Introduction

During the past year, the major effort of the National Bureau

of Standards has been devoted to the strengthening of its basic

programs. With the assistance of scientific advisory committees,

the Bureau is seeking: to develop a balanced technical program bv

increasing the level of research, especially basic research, in those

fields for which the Bureau has an assigned responsibility.

An effective standards research program must at all times

remain at the forefront of science. It must continually push to the frontiers in order to provide the new standards needed bv

scientists in their studies of new materials and newly understood

phenomena. Standards are important to scientific inquiry. They

are the results of meticulous investigation themselves. They are intimately associated with the basic units of measurement or comparison by which experiments may be properly described and

verified. Research associated with the development of standards

helps to unravel some of the puzzling results obtained with new

experiments and leads scientists and engineers to the best avenues

for the solution of their special technical problems. Thus, it provides clues for effective applied research and helps to eliminate false starts in development work.

By virtue of its responsibility for the custody, maintenance, and

establishment of the Nation's primary standards of physical

measurement, the National Bureau of Standards serves Government, science, and industry. The Bureau is the source for physical

standards used in mass production and in the development of

interchangeable parts—so vital to our modern economy. For

industry and science, the Bureau also performs critical calibrations

of working standards and distributes standard samples for use in production and research. For Government, the Bureau develops

methods for the acceptance testing of materials in procurement and

helps to devise codes and specifications. In addition, the scientific staff of the Bureau provides technical advice to various scientific and Government groups and undertakes a large variety of studies

to meet the special needs of other Government agencies.

Obviously, the work of the National Bureau of Standards is quite

broad. The scope of this responsibility is such that the Bureau

I
must continually adjust its programs to meet the most pressing

needs of the time. During the past three years the Bureau has

sought to attain an effective balanced level of research support for

the basic programs. This the Bureau is working toward.

1.2. Technical Activities

Standards and Measurements. As in previous years, a large part

of the technical program was concerned with scientific standards

and methods of precise measurement. A number of international

comparisons of fundamental standards were carried out. For

example, the national primary X-ray standard was compared with

the British standard, and the two United States primary radium

standards were compared with those of Canada and the United

Kingdom. The Bureau also cooperated with the International

Bureau of Weights and Measures at Sevres, France, in an international intercomparison of standard gage blocks, used to insure

uniform dimensions in mass production. Several improvements

in equipment and measurement techniques led to increased

accuracy of electrical measurements, particularly at audiofrequencies. Among these were improved guarding and shielding for resistance and capacitance standards and development of a bridge

circuit for measuring core loss in steel alloys. A technique was

devised for studying the performance of the highly sensitive microbalances used in such fields as atomic energy, where minute samples

must be weighed with high accuracy. Two devices were developed

that precisely measure radiation in terms of the heating effect it produces. One of these, a radiation-balance microcalorimeter,

will aid materially in meeting the increased demand for calibration

of radioactive sources. The other, an X-ray calorimeter, will serve as a basic standard for measurement of the high-energy

X-rays now being used in medical treatment and industrial radiography. To meet the increasing demand for standard samples of

radioactivity, a radiochemistry laboratory was established. The

new laboratory will prepare and distribute approximately 57

different radioactive nuclides and ores to hospitals, research

laboratories, and industrial plants.

Recent advances in electronics have emphasized the need for adequate standards and measurement techniques in the relatively

unexplored microwave region of the radio spectrum. Develop2
merits in this extreme high-frequency range included a self-balancing

bolometer bridge which brings increased speed and accuracy to microwave power measurements. Another instrument was devised

which makes possible coaxial impedance measurements to high

accuracy over a wide range of microwave frequencies. Progress was also made in developing reliable voltage-transfer standards

for frequencies up to 600 megacycles per second.

With the development of jet and rocket propulsion, vibrations

in high-speed aircraft and guided missiles must now be measured

over wider ranges of frequency and amplitude than ever before.

As partial fulfillment of this need, a high-resolution system was

designed and built for calibrating vibration pickups over the broad

frequency band from to 50,000 cycles per second. Vibration

standards were developed, and a limited calibration service for

vibration pickups measuring displacement, velocity, or acceleration was established.

During the year the Bureau redetermined the velocity of light

in two independent measurements by quite different methods.

The two values are in close agreement and thus provide confirmation for the higher values of electromagnetic wave velocity that

have been consistently obtained by microwave measurements

since World War II. In one method the velocity of light was

determined from measurement of the molecular constants of

carbon monoxide by infrared spectroscopy. The other determination made use of phase-shift measurements on very-high-frequency

radio waves to obtain their velocity of propagation. Before World

War II the value 299,776 ±4 kilometers per second was generally

accepted as an average of the findings of the various laboratories.

However, since the war higher values have been obtained by most

investigators (average value, 299,793 ±1 km/sec). The results

obtained by the Bureau give 299,792=h6 km/sec by the molecular

constants method and 299,795.1 ±3.1 km/sec by the radio interferometer.

Several measuring instruments were devised for specific purposes.

For example, an instrument, using microwave principles, was developed for rapid, accurate measurement of atmospheric water

vapor, particularly in the upper air. It will provide aerological

data for operation of high-performance aircraft. In connection

with a study of spectacle lenses for the Veterans Administration,

3
the Bureau developed an instrument that accurately measures both

central and marginal powers of a spectacle lens. Previously there was no completely satisfactory method for measuring the accuracy

of a spectacle lens at points other than the optical center. Although

the NBS instrument is basically a research tool, its essential principles have been utilized to design marginal-power attachments for

the standard vertex-power instrument used by practicing opticians.

Properties of Materials. In studies of the basic properties of

materials, increased emphasis was placed on those inorganic materials that are stable at very high temperatures. Data on such

materials are required for further advances in atomic power plants,

high-speed missiles, and jet aircraft, but information on their

high-temperature behavior has been lacking. In one project,

cermets—heat-resistant ceramic-metal combinations—were studied

in connection with their use in jet engines and rockets. The need

for nuclear reactor design data prompted an investigation of the

high-temperature reactions of uranium dioxide with other heatresistant compounds. High-temperature concretes were studied

to obtain materials for jet aircraft aprons that can withstand

exposure to high, variable temperatures. As part of a cooperative

interlaboratory study of the extractive metallurgy of titanium,

the Bureau prepared selected titanium compounds of high purity.

Included were titanium tetrachloride of 99.999-percent purity and

99.998-percent titanium tetrabromide. Other work in the hightemperature field concerned ceramic coatings for protection of

high-temperature alloys or for use as high-temperature insulation,

diffusion of gases in glasses, phase equilibria of refractory materials,

and thermal decomposition mechanisms of inorganic materials.

In the field of high polymers, pressure porosimeter and electron

microscope studies provided new insight into the structure and

behavior of leather. This work revealed the presence of large

numbers of extremely small pores—less than a millionth of an inch

in radius—in both leather and its parent substance, collagen. The

quantitative information obtained on pore-size distribution within

the individual collagen fibrils should aid the leather technologist in

understanding the swelling and shrinkage accompanying waterleather interactions. It is also expected to shed additional light on the ability of leather to transmit or absorb water vapor, tannins, or impregnants.

4
Electronic Computing. Large-scale processing of numerical data

has become a major management undertaking in Federal agencies

Not only are data processing problems encountered on a massive

scale in government, but frequently they are of such special nature

as to require unique design and research services. To provide an

advisory center for Government agencies on electronic computing

and data processing techniques, a data processing systems laboratory was established as a separate division of the Bureau. Combining NBS programs in analog and digital computers, the new

division carries on research, development, and systems design and

analysis in these fields. The new division working with the

Applied Mathematics Division places the Bureau in a stronger

position to advise on the use of high-speed computing techniques

in many new areas of potential application—such as massive paperwork operations, automatic control systems, and simulation of physical systems.

During 1955 the Bureau's high-speed electronic digital computer, SEAC, continued in round-the-clock operation except for a 2-month period required to move it to a new permanent location on

the Bureau grounds. Problems were solved in Government

procurement and industrial mobilization as well as in aerodynamics, atomic energy, meteorology, thermometry, optics, nuclear

physics, thermodynamics, sound, and navigation.

Research on individual computer components led to the development of a new type of diode amplifier that promises to play an important part in the future design of high-speed computers.

This compact, rugged device uses germanium or silicon crystals

instead of vacuum tubes. Because of its economy and speed of

operation, it appears to offer a means for increasing the practical

operating speed of present-day electronic digital computers.

In computer components work sponsored by the Naval Research

Laboratory, a gas-diode memory circuit was developed for use in a data correlator and classifier. This circuit should find application

wherever computed data must be presented for rapid visual

analysis. In another project sponsored by the Air Force, packaged

circuitry was designed which combines increased logical capabilities

with greatly decreased power consumption. These computer

packages should make feasible the building of larger and more

powerful computing machines without the need for excessively

large power supplies and air conditioning equipment.

5
Electronic Technology. A study undertaken for the Navy

Bureau of Aeronautics showed the feasibility of standardizing many

of the electronic circuits used in Navy aeronautical equipment.

Known as the NBS-BuAer preferred circuits program, this continuing investigation seeks to determine those well-known circuit

configurations that are common to a wide variety of electronic

devices but which now differ unnecessarily in detail. A number

of preferred circuits have been selected and prepared for joint

NBS-Navy publication as a manual for design engineers.

Although use of the circuits is entirely optional, their application

should save critical engineering man-hours, reduce production lead

time, and accelerate production. Preferred circuits should also

provide the military services with means for simplifying maintenance training, for designing simple "throwaway" units, for

achieving improved operational reliability, and for establishing

design standard levels. Another industrially significant program concerned the automatic production of electronics. Practical methods for modular

design and mechanized production of electronics have resulted

from a long-range program sponsored at NBS by the Navy Bureau

of Aeronautics. First announced in 1953, this new approach to electronic mechanization makes use of stacked ceramic wafers,

each bearing printed or applied resistors, conductors, capacitors,

and other parts. Some 4 to 6 wafers make up a module, corre- sponding to a stage of an electronic device. The uniformity and

simplicity of the parts make the modular system particularly suited

to mechanized production.

In the past 2 years the modular design and mechanized production concepts have stimulated extensive industrial interest and

have resulted in similar developments in industry. To further

industrial preparedness, the Navy is encouraging the use of modular

concepts in the production of several special naval equipments.

Thus, during 1955 the NBS modular electronics program was

concerned largely with indoctrination and training of manufacturers

and of industrial and military users of modular designs and techniques. Toward this end, an agreement was made for the Aerovox

Corporation to operate the Bureau's pilot line for experimental

mechanized production of electronic equipment. This agreement

should help broaden the Nation's experience and knowledge re6
garding use of modular design concepts in military equipment.

NBS research in modular design was mainly directed toward

improvements in specific modular components and fabrication

techniques. For example, new resistor formulations and new

techniques for applying resistors and capacitors to the ceramic

wafers were developed.

Calibration^ Testing, and Standard Samples. One of the important services of the Bureau to science and industry is the

comparison of working standards with the national standards of

measurement. Such calibration services are vital to industrial

production and progress, for all working standards in this country

depend upon calibration in terms of the national standards maintained by the Bureau. The Bureau is also responsible for testing

many of the materials—usually raw materials like cement—that

are purchased by Federal agencies.

During 1955, approximately 174,000 items were calibrated or

tested. Typical of the calibration activity were the following:

694 standard cells, 839 radium sources, 491 sources of radioactive

cobalt, 750 items of radiological equipment, 757 hydrometers, 994

water current meters, 33,110 clinical thermometers, 2,400 dilution

pipets. Testing for the Government included the sample-testing

of 3,000,000 lamps and 15,000,000 barrels of cement.

Approximately 32,500 standard samples of chemicals, metals,

and alloys were issued to industrial and research laboratories.

Standard samples are materials that are certified for chemical

composition or for some physical or chemical property, such as heat of combustion, melting point, or index of refraction. They

provide precise bases of comparison so that, for example, the

manufacturer of a chemical can control its purity by comparing

his product with the standard sample. Standard samples make

possible uniform measurements of heat and temperature, define

the colors of paints, and calibrate the instruments that control

the composition of synthetic rubbers and motor fuels. The list of standard samples issued by NBS now includes more than 500

materials.

Cooperative and Consulting Services. The Bureau is called upon

to provide technical and advisory services to almost every agency

of the Federal Government and to many State and municipal

governments. An example of this service is the development and

7
establishment of Federal Specifications. These specifications re- sult in purchase economies by establishing criteria which govern

quality and by providing opportunity for all businesses to compete

for Federal trade through the bid system. The Bureau also co- operates extensively with technical and trade associations both in this country and abroad, on problems of concern to the Government and the Nation, particularly those relating to the determination and establishment of scientific quantities and standards.

In addition, requests for technical information or advice are re- ceived daily from other Federal agencies, State and local governments, universities, industrial plants, and laboratories.

During 1955 services of an advisory or consulting nature were

rendered to a large number of government agencies. Typical

services included advice to the Post Office Department on automatic electronic equipment for processing mail; assistance to the

Virginia State Highway Department in calibrating equipment for testing highway signs; advice to the Civil Aeronautics Administration regarding the fire hazards of methyl alcohol solutions;

study of the causes of plaster failure in an Alaskan hospital for the Department of the Interior; consultative service on the ele- vators in the U. S. Capitol; advice to the Federal Trade Commission in the preparation of an amendment to the Flammable

Fabrics Act; suggestions to the National Zoological Park on flooring

for animal cages; assistance to the National Institutes of Health

in acoustical design of interview rooms; and cooperation with local

authorities in California and the Department of Health, Education, and Welfare on the smog problem.

The Bureau participated in the work of hundreds of technical

committees, societies, associations, and commissions organized to bring new advances of science into the technology of industry, to standardize materials and products for greater economy and

improved quality, and to establish uniform scientific standards

throughout the world. Bureau staff members held committee

memberships in more than 140 national and international groups

such as the American Society for Testing Materials, American

Standards Association, American Society of Mechanical Engineers,

American Chemical Society, and the International Committee on Weights and Measures. An important area of international

cooperation concerned the International Geophysical Year of

S
1957-58, during which scientists of 40 nations will make simultaneous worldwide observations of physical phenomena related to the Earth. Bureau staff members were active in both national

and international planning for the IGY and also rendered consultative services in connection with the design of observational

equipment.

1.3. Administrative Activities

The Bureau's activities are of two major budgetary classes:

First, the basic programs which are supported by direct appropriations from the Congress; second, various projects undertaken

for other Government agencies with funds transferred from these

agencies.

During 1955, the total funds obligated for both areas of activity,

including construction and facilities were $19,986,431. Of this

total, about 33 percent, or $6,575,331, came from direct Congressional appropriation for the basic program, while the remaining

67 percent, or $13,411,100, represented programs conducted for

other Government agencies. The bulk of the transferred funds

(all but $1,483,100) were provided by the Department of Defense

and the Atomic Energy Commission.

An objective of the Bureau management, acting in consultation

with its various advisory groups, is to increase the ratio of the

basic program to the total program. This can be accomplished

through increased fiscal support for the basic program and by more

selective screening of the projects in the transferred fund program.

Preference is given to transferred fund projects which are most

closely related to activities in the basic program.

During the past year, 12 technical committees were serving the

Bureau's scientific program (appendix, page 155). Composed of

prominent scientists and industrial representatives, these committees, which supplement the Bureau's statutory Visiting Committee (appendix, page 155), are a valuable source of consultation and stimulation and serve to bring to the Bureau the views

and needs of the Nation's scientists and technologists.

On September 14, 1954, President Dwight D. Eisenhower for- mally dedicated the NBS Boulder (Colorado) Laboratories. The

ceremony marked the completion and occupancy of the radio

laboratory building of the Central Radio Propagation Laboratory

which carries out the Bureau programs relating to radio standards

9
President Dwight D. Eisenhower formally dedicated the NBS Boulder Laboratories on September 14. The ceremony marked the completion and occu- pancy of the radio laboratory building by the Central Radio Propagation

Laboratory, one of the two major NBS activities making up the Boulder

Laboratories. In foreground of the air view of the Boulder Laboratories is the

Central Radio Propagation Laboratory, housing the three radio divisions. The Cryogenic Engineering Laboratory is located directly back of the Radio

Laboratory.

10
and radio propagation. Other events of the dedication program

included scientific conferences in the fields of research carried out

at Boulder. The Cryogenics Engineering Laboratory, previously

established on the Boulder site by the Bureau and the Atomic

i Energy Commission, became an integral part of the Boulder Laboratories. The Cryogenics Engineering Conference was the first national conference devoted entirely to engineering phases of lowtemperature research.

During the past year the Bureau held its first major Open House

in 17 years. More than 600 leading scientists and officials of

Government, industry, and universities participated in the program. The Open House, which covered the broad scope of the

Bureau's basic activities and their relationship to technological

progress, was designed to make more generally known the services

which the Bureau provides. The success of this Open House has

led to plans for making this type of presentation on a regular

basis. During the year, the Bureau re-established its tour program for the general public, supplementing the existing program

for scientific, professional, and other groups having a special

interest in NBS activities.

At the end of the reporting period, total employment at the

Bureau was 2,864. Most of the staff was stationed at the Bureau's laboratories in Washington, D. C. About 500 were located

at the NBS Boulder Laboratories, and at 20 field stations in the

United States and abroad.

1.4. Publications

The results of the Bureau's technical program are in general

embodied in its reports and publications. Even when the work is developmental in nature—for example, the development of a specific device—a report will represent the culmination of the activity,

and it is this report which will often prove of most value to Government, science, and industry. The reports and publications of

the Bureau are therefore suggestive of the scope of its activities.

During the year these totaled over 1,389, exclusive of calibration

and test reports and of general administrative documents. Some

825 classified and unclassified reports were issued to other Government agencies, particularly the Department of Defense, while over 440 papers and documents were published formally. Of the

367607—55 2
formal publications, some 124 consisted of scientific and technical

papers, 89 of which were published in the Journal of Research of the National Bureau of Standards (a monthly periodical) and the

remainder in the journals of various professional, engineering, and

trade organizations. In addition, approximately 65 summary

reports were published in the Bureau's monthly Technical News

Bulletin. The third monthly periodical of the Bureau, Basic Radio

Propagation Predictions, presented each month, for a 1-month

period 3 months in advance, radio-propagation data needed in determining the best frequencies to use in long-range radio communications.

Thirty-four papers were published in the Bureau's nonperiodical

series of publications: 8 in the Applied Mathematics Series, 4 in the Handbook series, 15 in the Circular series, 4 in the Building

Materials and Structures Report series, and 3 in the Miscellaneous

Publication series. A list of publications issued during the fiscal year is given in the appendix, section 5.5 (page 158).

2. Research and Development Program

The Bureau's technical program is carried out through organizational units called Divisions. These are shown in appendix 5.1. The review of the research and development programs is presented

in this section under headings corresponding generally to these

organizational units.

2.1. Electricity and Electronics

The work in electricity is primarily concerned with the development, improvement, and dissemination of the standards of meas- urement for electrical quantities and the studies of properties of

materials that are important in electricity and magnetism. The

object is to provide electrical standards that are as far as possible

constant with time, uniform throughout the nation, and consistent

with the more fundamental mechanical units. The work includes

the disseminating of standards for resistance, inductance, capacitance, voltage, current, power, energy, magnetizing force, and

magnetic induction.

The electronics activities include the standardizing of test methods for electronic components, studying materials and proc12
This floating weather station automatically reports meteorological data by

radio at regular intervals. It can be left unattended for 6-month periods

(p. 16). esses for component fabrication, establishing optimum designs of electronic equipment for maximum life and reliability, and co- operating with other Government agencies and industrial groups

in formulating codes and specifications. In areas in which the

Bureau is uniquely qualified electronic development programs are undertaken to meet the special requirements of the Bureau and

other Government agencies.

Fundamental Electrical Units. As a check on the fundamental

electrical standards, several preliminary determinations of the

absolute value of the ampere were made with the Pellat current

balance. The values obtained show that the ampere as currently

maintained by NBS standards is in satisfactorily close agreement

(within 10 parts per million) with the theoretically defined absolute

unit. During the past year standard resistors and saturated standard cells were exchanged and their values compared with those of

other nations at the International Bureau of Weights and Measures

at Sevres, France. Standard cells were also exchanged with the

Physikalisch-Technische Bundesanstalt of Western Germany.

The U. S. national standard for the volt has been maintained

for some years by a primary group of 23 saturated cells. As a

further step in assuring continued reliability of the standard, this

number was increased to 48 this past year by including an additional group of cells which have shown unusual stability over a period of 5 years. 13
Electrochemistry. Voltaic cell combinations of electrodes and

electrolytes are becoming increasingly important as reliable constant-voltage sources for aircraft and other technological applications. Under way are studies of Ag/Ag20, NaOH, and HgO/Hg

cells under carefully controlled conditions of purity and measure-- ments. Results indicate that after construction of the cell, the

potential first increases and then decreases several hundredths of

a volt. These changes represent a significant discrepancy from

the heat data calculations, and show a need for repeating the

earlier fundamental measurements on which the electrochemical 5 constants are based.

The increased interest in storage batteries for special applications has focused attention on types other than the common

lead-acid cell in general automotive use. Studies are under way

on modifications of such secondary batteries as the alkaline nickel

and iron electrode type, the nickel and cadmium type, and the

recently suggested zinc and silver-oxide type.

Improvements in Measuring Techniques. Recent improvements

in equipment and in measurement techniques have led to increased

accuracy of electrical measurements, particularly at audiofrequencies. Among these improvements are: (1) improved shielding in

air capacitors so that they are less affected by stray capacitance

in the course of 400-cps measurements for determinations of the

ratio and phase angle of computer-type transformers; (2) the introduction of guarding and shielding for precise determination of

phase defect of four-terminal resistance standards at audiofrequencies; (3) development of a bridge circuit for the measurement of

core loss in silicon steel and other steel alloys up to much higher

inductions than previously possible; and (4) the application of

both a modified 60-cps bridge circuit and the Bureau's precise

transfer wattmeter to obtain concordant results when measuring

the residual phase defect of a large air-core-power reactor. This

reactor will give a basis for similar measurements by industrial

laboratories on power transformers of the largest sizes. A pre- liminary model of an electrothermic wattmeter has also been

constructed that has an accuracy of about 0.03 percent in the

audio range.

A more rapid method announced last year for precisely measuring the rate of a-c watt-hour meters is now in regular use by the

14
Bureau. The method minimizes the use of an electrodynamic

wattmeter and avoids the laborious process of holding the a-c power constant while the meter registration is accumulating. In

lieu of regular use of the wattmeter for all tests, measurements

may now be made by a comparison process that employs a group

of carefully selected watt-hour meters. One of the meters is adapted

for use as a standard while the others serve as comparison standards. Rate comparisons are performed by comparing the number

of revolutions of the disk of the meter under study with that of

the standard. The standard meter must, of course, occasionally

have its rate determined by the older wattmeter method.

Resistor Noise. Under the sponsorship of the Navy Bureau of

Aeronautics systematic studies have been continued on the electrical noise generated in the composition resistors widely used in

electronic gear. Electrical noise, i. e., spontaneously generated

spurious electrical signals, may appear as audible noise in apparatus whose output is sound, but even where this is not the case

the presence of electrical noise in resistors limits their usefulness

for many applications. The work has required the development

of new types of measuring equipment for determining the inherent

noise characteristics of resistors, and the performance of a variety

of tests on existing types of filamentary and other resistors, to develop an acceptable basis for comparing the resistors. Results

of the investigation include readily reproducible methods of measurement, and will provide a basis for orderly practices for the

procurement of resistors by military specifications.

Electron Tubes. Electrical conduction by thermal electrons in

the pores of oxide-coated cathodes plays an important role in cathode characteristics. To study this effect, electron tubes having

oxide-coated cathodes with different degrees of coating porosity were constructed and investigated. Other experiments show that

tube life is closely related to the rate of sublimation of cathodic

materials. A very sensitive microbalance has been installed for

the measurement in vacuo of such sublimation rates. As a tool for studies of these kinds, a cathode emission tracer that provides a rapid, convenient method for measuring and

evaluating the performance of thermionic cathodes was developed.

The instrument automatically displays on the screen of a cathoderay oscilloscope a calibrated plot of the emission characteristics of

the cathode under study.

15
Research on Electric Spark Discharge. Using chopped voltage- wave techniques to produce very brief (i. e., less than one-millionth

of a second) electrical discharges between a sphere and a plane,

oscillograms of the spark current have been obtained so that

current measurements can be associated with the photographs of

the initial stages of the discharge. The beam-intensified cathode

ray oscilloscope developed earlier at NBS makes possible this

detailed study of the mechanism of electric breakdown in air. Pole-top Failure. With the support of the Rural Electrification

Administration the Bureau has investigated lightning failures of

equipment mounted at the top of poles used for electrical distribution circuits. Tests with very large artificial surges of voltage and

current revealed that the most common types of field failures could

be duplicated in the laboratory. On the basis of these tests the

positions of some of the conducting elements on the pole were changed and gaps were relocated. Repeated laboratory surge tests demonstrated that with the new pole-top arrangement injury from

lightning would not result. This work has resulted in new specifications for the layout of the pole-top hardware and for grounding

conductor locations. The new specifications will apply to existing

and proposed installations on more than 5 million poles.

Design of Mutual Inductance Transducers. The mutual induct- ance transducer, developed earlier at the Bureau, has found wide

application in electronic distance-measuring instruments. The

transducer detects extremely minute changes in the position of a nearby conducting plate and can be made to record such changes

with an accuracy of 5 percent or better. Until recently, design

analysis of the transducer has been restricted to its immediate

use in a particular instrument. Because of the need for general

design criteria for use in future applications, the Bureau made a

detailed study of the device's operating principles with major

emphasis on transducers using highly conducting reference plates.

The results include a number of design recommendations for obtaining optimum combinations of sensitivity, stability, and linearity over the range in which the instrument is to be used.

Marine Weather Station. Preliminary tests of a prototype automatic marine weather station, developed for the Navy Bureau of

Aeronautics, were completed in Chesapeake Bay. The unit is incorporated into a buoy that can be anchored in remote locations.

16
It provides for unattended operation over long periods of time,

and reports meteorological data by radio link at regular intervals.

Also, eight hurricane detection buoys, with appropriate sensing

and radio transmitting equipment, were designed and constructed.

Special Electronic Devices. Several electronic devices were made

available for specialized application within the Bureau or bv other

Government agencies. One of these is an 80-kilocycle amplifier

and synchronous detector for use in fundamental studies of the

microwave absorption lines of gases. Another device is detection

equipment for an electron-photon interaction study where it is necessary to discriminate currents of 10~13 amp at 450 cps. In the development of a compact wide-range receiver for the

Rome Air Development Center, one problem arose which could

be solved only by the design of a 24-section filter. This filter was constructed using miniaturization techniques and incorporates

quite simple but effective tuning adjustments.

A current problem of concern to the U. S. Weather Bureau is accessibility to permanent meteorological records. The volume

of such records in the form of punched cards has become a serious

problem. The storage problem can be alleviated by storing microfilm records instead of the bulkier cards, but no automatic reading

device for records in this form has hitherto been available. Such

equipment is now in process of development at NBS for the

Weather Bureau. The practicability of the proposed operating

principles has been demonstrated.

Preferred Circuits. Studies leading to the standardization of

electronic circuits have been continued for the Navy Bureau of

Aeronautics. In the absence of such standardization, detailed

circuits designed to perform identical functions in a variety of

complex electronic devices, may differ widely in the kind of parts,

their numerical values and circuit arrangements. Where the component circuits have been standardized, great savings in engineering design time and great reductions in the diversity of electronic

parts to be stocked have resulted. Gains in performance and

reliability are also possible if suitable care is taken in the initial selection of a "preferred" circuit. The program was organized to

select such preferred circuits from the large numbers of established

designs. A number of preferred circuits have been selected and

prepared for joint NBS-Navy publication under the title "Preferred

17
The NBS-BuAer preferred circuits program is designed to aid electronic equipment manufacturers and military users. Preferred circuits can be

applied to both conventional and modular construction techniques (p. 17). Circuits Manual, Navy Aeronautical Electronic Equipment."

Use of the circuits is entirely optional.

Mechanized Production of Electronics. Under the sponsorship of the Navy Bureau of Aeronautics, the Bureau has continued

certain phases of its program of modular design and mechanized

production of electronics. The NBS modular design and mechanized production concepts, developed as a military preparedness measure and originally announced in 1953, have stimulated extensive interest and similar developments in industry. The main

emphasis of the Bureau's current program is to indoctrinate and

provide a suitable training program for manufacturers as well as industrial and military users of modular designs and techniques.

This is in keeping with the Navy's preparedness policy of en- couraging the use of modular-design concepts in the production of

several special naval equipments. Toward this end a facilities use agreement was recently made with the Aerovox Corporation

which will operate the NBS pilot line for mechanized production

of electronic equipment. The agreement is designed to broaden

the Nation's base in experience and know how for the use of

modular design concepts in military equipment. Several manufacturers are now producing or are preparing to produce the

modular design essentially as originally developed.

IS
A step in the making of tape capacitors for the mechanized production of electronics program (p. 18). During the past year research efforts were directed toward

improvements in specific modular components and fabrication

techniques. The quality of the tape resistor is being improved

through (1) use of a recently developed curing oven that has

extremely accurate temperature control, (2) development of new

resistor formulations, and (3) new techniques of spraying and

attaching resistors and capacitors to ceramic wafers. Results to date indicate that it is possible to make by mechanical means

high-quality resistance and capacitance units that are more stable

and accurate over a wider range of operating conditions than

heretofore attainable. Under study are methods for incorporating

the manufacture of the cracked carbon and boro-carbon resistors

into the regular production line.

2.2. Optics and Metrology

The Bureau's work in optics and metrology was principally

concerned with problems of measurement, instrumentation, and

standardization. Fields of activity included photometry, colorimetry, optical instruments, photographic technology, interferom19
etry, thermal expansion, and calibration of line and end standards. In addition, specific development programs were carried

out for other Government agencies. Typical projects dealt with

intercomparison of length and optical standards, optical properties

of spectacle lenses, aircraft and airport lighting, indices of refraction

of synthetic crystals for infrared applications, measurement of

atmospheric transmission and its application to airplane landings,

and application of high-speed computers to lens design.

Intercomparison of Standards. The National Bureau of Standards cooperated with the International Bureau of Weights and

Measures and the other national standardizing laboratories in an

international intercomparison of standard gage blocks. Gage

blocks approximately 2, 3, and 4 inches (50, 75, and 100 mm) long were submitted to the International Bureau of Weights and

Measures at Sevres, France, after their lengths had been carefully

measured by the participating laboratories. Results have not

been completely reported, but indications are that for all countries

approximately two-thirds of the measurements reported to date

agree within two-millionths of an inch.

Line standards, such as the meter bar, and end standards, such

as gage blocks, are ordinarily measured by different procedures.

During the past year, NBS inaugurated a program for intercomparison of its line and end standards. Preliminary results

indicate that the two sets of standards are consistent.

During the past year, NBS calibrated 32 electric lamps, in 4

groups of 8 each, for intensity at 2,042° K, intensity and luminous

flux at 2,353° K, and luminous flux at 2,788° K. These three

temperatures are, respectively, the temperature of a complete

radiator at the freezing point of platinum (the international

standard of luminous intensity), the approximate temperature of

the filament of a vacuum tungsten lamp, and the approximate

temperature of the filament of a gas-filled tungsten lamp. Four

from each group of eight lamps were taken to the International

Bureau of Weights and Measures to be calibrated against its standards and also to be compared with the standards of other

national standardizing laboratories.

Determination of Color Differences. Accurate matching of

colors is becoming increasingly important to modern industry.

20
Household appliances such as stoves, refrigerators, washing

machines, and clothes dryers may be assembled from parts produced on different production lines and finished with different

materials. A noticeable color difference between parts may be

objectionable to the customer and may hurt the sale of the product.

Likewise, for many other uses, such as advertising signs, trademarks, traffic lights, and railroad signals, color is rigidly specified

and closely controlled.

For many years manufacturers and purchasers of colored

materials have employed inspectors to determine whether or not

two samples are sufficiently similar in color to be called a "match".

Frequently inspectors cannot agree, and in recent decades instruments have been developed to measure color and color differences

precisely. But the extent to which instrumental values of color

differences agree with estimates of human observers is a question

that has never been satisfactorily resolved.

To obtain data which may lead to a solution of this problem,

the Bureau, in cooperation with the Porcelain Enamel Institute,

embarked some years ago on a long-range research program.

Although much experimental work remains to be done, preliminary

phases of the investigation have provided significant information on the evaluation of color differences. This initial stage of the

program has been carried out by personnel of NBS and of Hunterlab, with the cooperation of a number of industrial laboratories.

While the extent to which instrumental measurements of color

difference correlate with visual estimates has not been completely

determined, useful conclusions can be drawn from the results

obtained thus far. In general, it appears that color-difference

meters properly operated are likely to be more reliable than the

estimates of a single observer or even a small group of observers.

Correlation of instrumental measurements with visual estimates

will probably be satisfactory in most cases but should be verified

for each color where such correlation is important. The numerical

size of an instrumentally measured color difference will depend on

the instrument and the color-difference equation used.

Glass Color Standards. Many commercial products—such as foods and vegetable and mineral oils—are graded on the basis of

color. To maintain consistency of grading in different parts of

the country, standard sets of colored glasses are used. These

21
NBS attachments for measuring marginal power of spectacle lenses are shown

in place on a standard power measuring instrument used by practicing

optometrists.

standard glasses can be combined to produce a very large number

of different standard colors which are matched with the product

to be graded.

After some 4,000 of these glasses had been submitted to the

Bureau for calibration, a statistical study was made of the data.

The study shows (1) the ideal system of colors with which the

glasses should comply if the colors presented by the combination

of glasses are to be correct, and (2) the deviations which may be

expected. The results of this work are made available to users of the glass standards by a calibration service which gives users

the differences between the nominal and actual color. Spectacle Lenses. The Bureau completed an investigation of

spectacle lenses sponsored by the Veterans' Administration. The

project involved performance studies of corrected spectacle lenses,

which are designed to give approximately the same visual correction through the central and peripheral parts of the lens. A special

instrument was designed for making the required measurements.

22
Experimental model of approach beacon system for jet aircraft in marginal

weather.

This instrument accurately measures the power of a lens at the

periphery as well as at the center. The data thus obtained were

used to prepare specifications indicating the performance that is generally realized by commercial lenses. Formulas were derived

for computing the astigmatism along any principal ray for a lens,

such as a spectacle lens, composed of spherical and toric surfaces.

Aviation Lighting. At the request of the Air Force, a comprehensive study was made of the operational requirements of airfield lighting systems for jet aircraft, and a system meeting these needs was designed. A system of approach beacons for use in marginal

weather was designed and field-tested.

The Bureau collaborated with the Rohm & Haas Company and

the Civil Aeronautics Administration in developing a green plastic

for use in place of glass in aviation lighting equipment. The

resulting material is not only less expensive than glass but has

better colorimetric characteristics and is much lighter. The reduction in weight is of great advantage to airway mechanics who

frequently must carry the 2-foot beacon covers on foot up steep

mountain slopes.

An eye-level warning light for aircraft instrument panels was

developed for the Navy Bureau of Aeronautics. The light is small enough to be mounted on the cowling above a cockpit in- strument panel, close to the pilot's normal line of sight without

23
material interference with his vision. The device warns the pilot

by appropriate illuminated legends when any part of the aircraft

essential to flight or landing is not operating properly.

Refractometry of Synthetic Crystals. During World War II, methods were developed for producing large, transparent synthetic

crystals, suitable for lens construction, of such materials as calcium

fluoride, lithium fluoride, silver chloride, and cesium iodide.

Many of these crystals are transparent to the infrared and are therefore of great importance in connection with the increasing

interest in this spectral region. However, before they can be

generally useful in lens systems, their indices of refraction must

be measured throughout the spectral region within which they

transmit light.

During the past year the Bureau measured indices of refraction

and their change with temperature for sodium chloride, cesium

iodide, and arsenic sulphide (As2 S3 ) in the ultraviolet, visible, and

infrared portions of the spectrum. The index of refraction was

also measured for four infrared glasses, and an interferometric

method was applied to measure the index of refraction of Canada

balsam. In connection with this work, an interferometric method

was developed for determining the uniformity of the index of

refraction within large disks of optical glass.

2.3. Heat and Power

To provide a fundamental basis for precise measurements of

heat and power, the Bureau maintains temperature scales covering

most of the range from the lowest obtainable temperature to the

highest temperature of incandescent bodies and flames. The

Bureau is also responsible for determining and maintaining standards of viscosity, heat capacity, and heat of combustion; it maintains the primary standards for determination of the octane number of automotive and aviation fuels. Research is conducted to increase the accuracy of these standards and to develop improved

measuring instruments and apparatus.

From the standards of temperature, the work in heat and power

broadens to include the determination of quantities of heat by

calorimetry at temperatures extending over a large part of the

scale. Concurrent theoretical programs relate thermal properties

to molecular structure and permit the calculation and compilation

of tables of thermal properties over an even wider temperature

24
range. Particular emphasis is placed on investigations of electrical, magnetic, and thermal properties of matter at extremely

low temperatures. In cooperation with the research programs of

medical agencies, the Bureau applies thermodynamic techniques

to the measurement of biologically important materials. Rheological studies, dealing with the flow characteristics of lubricants

and of rubber solutions, are also conducted. From these fields of

activity, the work in heat and power extends to research on the

mechanism of combustion in engines, bearing and lubrication

studies, high pressure pneumatics, and applied thermodynamic

investigations of such heat engines as compressors and internal

combustion engines.

Temperature Standards. Recent years have brought an increasing need for more accurate measures of temperature on the fundamental Thermodynamic Scale. To meet this need, the Bureau

began a 5-year program of gas thermometry covering temperatures

from somewhat above the ice point up to 800° C. Objectives of

the program include the accurate determination of the thermodynamic temperature of the sulphur point and measurement of

differences between the Thermodynamic Scale and the Inter- national Temperature Scale. The latter scale is a practical scale

which is commonly used in laboratory measurements.

Other research seeks to develop and improve temperature scales

in the very low and very high ranges. During the past 2 years

the inaccuracies in the presently accepted helium vapor-pressure

scale of temperature between 1° and 4° K (—272° to —269° C)

have become recognized as a serious problem. The Bureau has

been using its magnetic thermometer to investigate this region.

Results to date are in excellent agreement with those of other

laboratories below 2.17° K, but discrepancies exist above this,

point. Efforts are being made to identify possible sources of

error. Below 1° K, gamma irradiation from cobalt-60 sources was

established as a project facility for low-temperature calorimetry,

and new measurements were made upon the paramagnetic salt,

chromic methylammonium alum, down to the region of 0.01° K.

The major aims of this work are to improve measurement techniques and to resolve major discrepancies in order to establish an

accurate temperature scale in the neighborhood of absolute zero.

25
A new technique for studying the processes of nuclear disintegration is pro- vided by alinement of radioactive nuclei. The experiments are conducted

at temperatures near absolute zero using this equipment (p. 27). In the high-temperature range, advances were made in a spectroscopic investigation of flames and hot gases. This program is sponsored by the Wright Air Development Center. Its long-range

objective is to develop methods of measuring and interpreting

temperatures in gaseous systems. The radiation from such sys- tems is studied in detail as a function of various parameters such

as temperature and pressure. Important phases of the work

include analyzing newly observed bands and improving the analysis

of known bands. In the infrared region, intensities and line half- widths of carbon monoxide were investigated to permit more

accurate evaluation of flame temperatures. A method for measuring population "temperatures" in absorption was developed. This

method, which uses the logarithm of the inverse of the minimum

transmission, rather than percent absorption, is especially valuable

in treating cases showing very strong self-absorption.

Low-Temperature Research. At liquid-helium temperatures

metals such as lead and tin completely lose their electrical resis- tance. The Bureau has been studying this phenomenon, known

as superconductivity, under the sponsorship of the Air Research

26
Ju. #*** if *. Magnified (1,000 times), a tin "whisker" 1 micron in diameter is shown

mounted between silver paste electrodes for superconducting and phase

transition studies at liquid helium temperatures.

and Development Command. During the past year the superconductivity program dealt largely with an unusual class of tin crystals called "whiskers. " The interest in tin whiskers stems

primarily from their size—about 1 micron in diameter. As the

surface-to-volume ratio of a superconductive wire becomes large, as in the case of tin whiskers, size effects occur. A study of these

effects provides information about the surface tension between

superconducting and normal domains and about the penetration

of a magnetic field at the surface of a superconductor. Recent

results indicate that domain segmentation is not possible in tin whiskers under certain conditions which ordinarily favor such a

structure. This has been explained in terms of a prohibitively

high interdomain surface energy in filaments of this size. The

Bureau is now seeking a more precise expression of these results

and is investigating the effects of magnetic field penetration on

the phase transition in tin whiskers.

In 1954, the Bureau achieved alinement of radioactive nuclei in

367607—55 3 27
a low-temperature investigation sponsored by the Office of Naval

Research. These results were obtained in a study of gamma-ray

emission from 30-day cerium-141. During 1955 further experiments of this type were carried out with two isotopes: 11-day

neodymium-147 and 140-day cerium-139. Work was also begun

on a new method of polarizing nuclei (Overhauser effect), by which

it should be possible to work in a more convenient temperature

range, and also to orient a larger number of different nuclei. The

method depends on the saturation of electron paramagnetic

resonance signals.

Interesting phenomena were observed when gaseous oxygen and

nitrogen were subjected to a high-frequency electrodeless discharge

at reduced pressure and then cooled rapidly to the temperature of

liquid helium. It appears that these phenomena are caused by

free atoms and radicals, such as atomic oxygen, atomic hydrogen,

and hydroxyl (OH), which do not exist under usual conditions.

The solid condensed from nitrogen at 4.2° K emits a bright green

glow with occasional blue flashes. The spectra from these glows

have been tentatively interpreted as due to interaction of the solid

lattice with atomic and molecular nitrogen. Oxygen products

condensed at 4.2° K appear as a transparent, glasslike substance.

When the temperature is raised, the original deposit evaporates,

and solid violet material is condensed on the surface. The violet

substance has been identified as ozone.

Properties of Air and Related Substances . A comprehensive

investigation of air and its principal constituents, conducted for the National Advisory Committee for Aeronautics, the Air Force,

the Navy, and the Atomic Energy Commission, produced extensive

compilations of data as well as a variety of experimental and

theoretical procedures. The need for data required extension of

temperature and pressure ranges. Thus, to help solve problems

of condensation in hypersonic wind tunnels, measurements were made on phase equilibria in oxygen-nitrogen mixtures at temperatures as low as 65° K, on the heats of vaporization and surface

tension of oxygen-nitrogen mixtures, and on the condensation line

of air. To provide high-pressure data for aircraft pneumatic

systems and other applications, data of state were measured for air over a wide range of pressures from room temperature down to 125° K. Apparatus was built for very precise thermal-conductivity

measurements on gases under pressure. It is expected that this

28
apparatus will supply data sufficiently precise for theoretical pre- diction of the pressure dependence of the transport properties at moderate pressures. Measurements were completed on the thermal

conductivity of nitrogen to 100 atmospheres and 500° C.

Various research and technical applications now require adequate

values of the properties of air and other gases at temperatures up

to 15,000° K. Work in this area required extension of the methods

of statistical mechanics. The ideal-gas thermodynamic properties

of atoms and ions and of diatomic molecules were calculated to very high temperatures.

The Bureau compiled and published the thermodynamic and

transport properties of air, argon, carbon dioxide, carbon monoxide,

hydrogen, nitrogen, oxygen, and steam. Another extensive calculation of tables was completed covering the ideal gas thermodynamic functions and equilibrium constants for isotopic exchange

and substitution reactions for over a hundred diatomic hydrides,

deuterides, and tritides. Thermodynamic Properties of Metals and Salts. In recent years

the importance of metals, alloys, and salts has been greatly ex- tended by the rapid technological growth in atomic energy and

aerodynamics. In designing for optimum efficiency in power

generation and high-speed flight, many metals and salts are now

extensively used in liquid form for heat transfer. The success of

many high-temperature processes depends on the ability of these

materials to resist chemical decomposition or volatilization.

There is thus a need for more accurate thermodynamic data on

metals and salts. In cooperation with the Atomic Energy Commission, the

Department of Defense, and the National Advisory Committee

for Aeronautics, the Bureau has for several years been endeavoring

to meet this need. In recent years it measured accurately the

heat capacities up to high temperatures of 18 metals and alloys

and of 14 salts, together with melting points and heats of fusion

and transition. From the heat capacity measurements, other

important thermodynamic properties, such as entropy and free energy, were calculated. New apparatus is now being constructed

to extend the range of measurements from 900° up to 1,500° C.

Mechanical Degradation of Polymers. Significant information on

the mechanical degradation of polymers was obtained by studying

29
the decrease in molecular weight of polyisobutenes when their

concentrated solutions were sheared through a capillary in the

NBS-McKee consistometer. In previous investigations mechanical degradation has been inseparable from pyrolytic and oxidative

degradation. The NBS study eliminated the effects of these latter

types of degradation. The distinguishing characteristic of mechanical degradation is that a polymer molecule must exceed some minimum size before it can be broken by this process under given

shearing conditions.

Molecular weight changes occur as a result of shearing during

the processing of many polymeric products such as elastomers,

plastics, and fibers. Mechanical degradation is also an important

consideration in the use of polymers as lubricating oil additives

to improve viscosity index and to lower pour point. Study of

the kinetics and energetics of the process promises to provide

valuable information about the entanglement of macromolecules

in polymeric systems.

Combustion in Engines. Continued investigation of the causes

of engine detonation, or knock, gave additional information on

this phenomenon. With paraffin hydrocarbon fuels, the onset of detonation was found to take place at a definite temperature

regardless of the structure of the hydrocarbon molecule. This

temperature, near 1,150° F, is obtained by a combination of heat

of compression and heat from cool-flame reactions occurring just

prior to detonation. If the increase in temperature due to coolflame reaction is small, as with higher-octane hydrocarbons, then

the heat from compression may be increased before the "detonation temperature'' is reached. Thus a high-octane fuel may be

burned in a higher-compression engine. Conversely, low-octane

fuels, which undergo rather extensive cool-flame reactions, may

not be compressed as much before detonation occurs. Isotopic carbon-13 atoms were used to trace carbon-carbon

bonds in combustion of a hydrocarbon. Contrary to some current

theories on formation of diatomic carbon molecules (C2) in flames,

C2 apparently results from a process in which the carbon bonds of

the fuel are broken early in the flame reaction and reformed

randomly to give C2 . The same technique was used to show that

the soot formed originates by a nonselective process involving

equally all the carbon atoms of the fuel molecule.

30
2.4. Atomic and Radiation Physics

Fundamental atomic and nuclear studies are important to other

research laboratories, medical institutions, industry, the military

services, and other Government agencies. The Bureau's program

in atomic and radiation physics is concerned primarily with studies

of (1) particles such as atoms, nuclei, neutrons, and electrons;

(2) properties of radiation, particularly gamma and X-rays and

ultraviolet and infrared light; and (3) the interactions between

such radiations and particles. Emphasis is placed on the fundamental research and development necessary to meet the increasing

demand for new standards, more accurate values of atomic and

nuclear constants, reliable data on the properties of high-energy

radiations, new and improved methods of measurement, and the

calibration of radiation sources and radiation detection instruments.

Velocity of Light Redetermined. The Bureau determined the

velocity of light from measurement of the molecular constants of

carbon monoxide by infrared spectroscopy. This work provides

confirmation for the higher values of electromagnetic wave velocity

that have been consistently obtained by microwave measurements

since World War II. The velocity of electromagnetic waves has been a subject of

investigation for many years. In the period preceding World War

II, the value 299,776 ±4 kilometers per second was generally

accepted as an average of the findings of the various laboratories.

However, since the war higher values have been obtained by most

investigators, largely through measurement of the velocity of

propagation of microwaves. Consideration of this more recent

work has led to an average value of 299,793 ±1 km/sec. The

Bureau obtained a value of 299,792 ±6 km/sec by the molecular

constants method. This value is in close agreement with another

value obtained independently at NBS by a radio-interferometer

method (page 107).

The molecular constants method was originally suggested by

Dr. A. E. Douglas of Ottawa, Canada. As applied at NBS it involved measurement of the frequencies not only of lines in the

infrared absorption spectrum of carbon monoxide but also of infrared emission spectral lines obtained when CO is produced in the

flame of a burning gas. Spectral lines corresponding to the rotational states only of the excited CO molecule were already available

31
from microwave spectroscopy. The Bureau measured other lines corresponding to both vibrational and rotational states by infrared

spectroscopy. The experimentally determined frequencies of the

spectral lines were then used to calculate values of the molecular

constants of CO which occur in theoretical formulas for the fre- quencies. The same molecular constants were obtained in both

the infrared and microwave equations, but they were in different

units: the microwave constants were in megacycles per second

while the infrared constants were in reciprocal centimeters. Thus,

the velocity of light could be calculated by taking the ratios of

corresponding molecular constants. The precision of this determination was due in large part to the

selection of the CO spectrum for investigation. This spectrum

has many spectral lines (both absorption and emission), from which

molecular constants can be obtained. Also, the use of flame

spectra made for greater precision by providing relatively large

values of the rotational quantum number /, which occurs in higher powers in the infrared equations.

Radiation Balance. A radiation-balance microcalorimeter has

been developed which precisely determines the emission rate of

low-activity radioactive sources. The instrument does this by

measuring the minute amounts of heat energy that accompany

radioactive emission. The device is extremely compact and re- quires a relatively short time to complete a determination. It can

be used to determine the intensity of a single source or to compare

two sources of nearly equivalent energy emission. The balance is expected to aid materially in meeting the increased demand for certification of radioactive sources. X-ray Calorimeter. The interpretation of experimental data

obtained with high energy X-rays generally depends upon an

accurate knowledge of the beam intensity. For research above

2 million volts, measurement methods developed for medium

energies are difficult to perform and often inaccurate. To meet

this need, the Bureau has developed a calorimeter for use as a primary standard in the measurement of high energy X-ray beam

intensities.

The calorimeter consists essentially of a lead cylinder of a size suitable for absorbing most of the X-ray beam. The temperature

rise in the lead cylinder due to the absorbed X-rays is compared

32
By removing electrons from the Bureau's 30-million-volt betatron in a beam,

it is possible to study the direct interaction of electrons with matter at a position remote from the betatron but near the electron target (p. 33). The

port, being adjusted at left, serves as the outlet for electron beams. The

magnetic extractor developed to make experiment possible is at right.

with the temperature rise produced by a measurable quantity of

electrical energy dissipated in the cylinder. The measurement

therefore supplies a direct comparison between X-ray energy and

electrical energy with an accuracy of a few percent.

Electron Beam Extractor. In order to extend the usefulness of

the betatron, several attempts have been made to remove the

electrons from the betatron in a beam. A magnetic extractor,

recently developed by the Bureau now makes it possible to obtain an external beam of electrons. Using this, the direct electron

interaction with matter at a position outside the betatron can be

studied.

The extractor employs a specially constructed coil that is inserted

into the vacuum chamber in a position to which the electrons can

be deflected. A pulsed current through this coil produces a local magnetic held of 5,500 gauss, which is sufficient to cancel the

main magnetic guiding held in that region. The electrons, upon

reaching this region, travel in an approximately straight path and

thereby escape from the guiding field of the magnet. The electron

beam has been successfully extracted from the betatron at energies

up to 24 Mev and with peak currents of the order of 5X10"10 amp.

New Radiochemistry Laboratory. New uses for radioactive iso- topes in physics, industry, and medical research and therapy have

increased tremendously the demand for NBS standard samples of

33
Interior of "hot lab" in the radiochemistry laboratory. Here solutions of radioactive materials are prepared for use as standard samples (p. 33).

radioactivity. To accommodate this increased demand, the Bureau has established a radiochemistry laboratory. The program

of this laboratory involves the preparation, maintenance, and

distribution of approximately 57 different radioactive nuclides and

ores, including carbon-14, sodium-22, phosphorus-32, and iodine131. Nuclides are distributed as solutions in small glass vials and

are specified at preparation time in terms of disintegrations per

second per milliliter. The resources of the new laboratory are expected to expedite greatly the Bureau's program of radioactive

sample distribution.

Attenuation of Gamma Rays at Oblique Incidence. An investigation has been conducted of the attenuation of gamma radiation

incident obliquely on barriers of lead, concrete, and concrete- equivalent materials. Results of the study, which was sponsored

by the Atomic Energy Commission, indicate that considerable

error may be involved in some estimates of protective barrier

thickness necessary to produce a specified attenuation. Estimates

based on attenuation data for normally incident radiation were

found to be several half-value layers low for obliquely incident

radiation of the same energy. Thus it is obvious that the additional factor of incidence angle must be considered in any plan

for construction of radiation protection barriers.

34
The automatic zone melter recently constructed at the Bureau provides a simple, inexpensive device for obtaining extremely high purity in semiconducting materials. It will also blend evenly, specific amounts of two metals

to obtain a desired alloy.

The XBS studv was initiated primarily to determine the dependence of the "obliquity effect" on variations in (1) incident

photon energy, (2) angle of incidence, and (3) barrier material for an initially parallel beam of radiation. Gamma radiation from

cobalt-60, cesium-137, and gold-198 was used at incidence angles

of 0°, 30°, 50°, 60°, and 70°. Zo)ie Melting Apparatus. An automatic laboratory-type zone

melter constructed at the Bureau combines versatility and dependability with unusual simplicity and ease of operation. The

device is now being used in the Bureau's solid state physics laboratory to obtain extremely high purity in semiconducting materials

and to produce a series ot mtermetallic compounds between the

metal antimony and the metals indium, gallium, or aluminum.

The zone melting process has been used to purify metals for several years and is now a familiar industrial and scientific tool. By this process it is possible in some cases to obtain such a high

degree of purity that the remaining impurities are undetectable by

present analytical methods. It is also possible to blend in evenly

a specific amount of another metal to obtain a desired alloy.

35
Internatioiial Ititercomparison of Radiation Standards. In 1953

the NBS primary X-ray standard was transported to the National

Physical Laboratory in England for comparison with the British

primary X-ray standard. At that time two important discrepancies were disclosed, and both of these problems have since been

under intensive study. The National Physical Laboratory has

now redesigned its standard, and this year it was brought to this

country. Comparison with the NBS standard showed an agreement of from 0.3 to 0.4 percent in the 60 to 250 kv range. This

international measurement in roentgens gave much better results

than the 1953 measurements, when differences of 3 to 7 percent were obtained.

Recently the British primary radium standard and the Canadian

national radium standard were brought to this country for comparison with the two United States primary radium standards

kept at the Bureau. The intercomparisons were conducted over

a period of 12 days and were made as exhaustive as possible, using

the NBS standard electroscope, a Peltier-effect radiation balance,

and Geiger and scintillation counters. The results closely confirm

the ratios of the weights of the British and the two United States

standards. However, a new weight, differing from its previous

value by approximately 0.5 percent, was derived for the Canadian

standard. Further work is expected on the intercomparison

program with Great Britain, Canada, and other interested countries. On the basis of the intercomparisons, plans have been

made to establish international standards of a number of nuclides,

beginning with phosphorus-32 and cobalt-60.

Negative Ion Research. The growth of the gaseous electronics

industry and the understanding of the nature of the earth's upper

atmosphere depend on knowing the properties and the behavior of

negatively charged atoms. In the upper atmosphere these atoms,

called negative ions, may influence radio communications by

changing the strength of the reflected signals from the ionosphere

layers. Although important to the physics of ionized gases, these

negative ions are very fragile, and hence very difficult to handle

experimentally. Since the theoretical elucidation of their properties is equally intractable, very little is known about even the

most important properties of atomic negative ions.

36
A significant break in this field of research has resulted from the

development at the Bureau of experimental apparatus for the

direct measurement of two of the ions' most important properties:

their binding energy and light absorption. Beams of negative

ions in very high vacuum are illuminated with very intense light.

This light detaches a minute current of free electrons, which is measured. Negative ions of hydrogen and oxygen have been

studied. It was discovered that the generally accepted value of

binding energy of the atomic oxygen ion is in serious error. The

new NBS value may provide the solution to a long standing contro- versy concerning the basic thermodynamic properties of nitrogen.

2.5. Chemistry

A wide range of fundamental and applied research in physical,

analytical, organic, and inorganic chemistry makes it possible for the Bureau to supply essential facts and data required by other

Government laboratories, industry, and science. Chemistry laboratories are devoted to a variety of subjects including organic

protective coatings, colloids, adsorbents, carbohydrates, metals

and alloys, electrodeposited coatings, gases, pYL standards, hydrocarbons, dielectrics, and pure substances. The techniques used

include analytical separations by ion exchange, radioactive labeling

of organic and inorganic compounds, emission and infrared spectroscopy, flame photometry, electrodeposition from fused salts and from

nonaqueous solvents, electrophoresis, and purification by growth

of single crystals. Industrial quality control and fundamental

research activities throughout the nation create a heavy demand

for NBS standard samples, most of which originate in this division.

Colloidal Dispersions. Some of the most interesting and

important types of collodial particles are formed in solution by

the reversible association of large numbers of small molecules or

ions. Termed association colloids, they are exemplified by such

diverse substances as detergents, dyes, and hydrous oxide precipitates. The colloidal aggregates formed in detergent solutions

are called micelles. Their structure is being investigated to throw

further light on the mechanism of detergency.

Typical representatives of the three main types of detergents

sodium dodecyl sulfate (anionic), dodecylamine hydrochloride

(cationic), and a polyoxethylene condensate of ditertiary butyl

37
phenol (non-ionic) —are being studied through measurements of

viscosity, light scattering, and electrophoresis. Viscosity and

light scattering studies provide knowledge of the size, shape, and

solvation of the micelles. From electrophoresis measurements

the electrical charge on the micelles can be evaluated. This, in

in turn, permits a more rigorous reinterpretation of the data on

micelle size and shape. Besides contributing to a better understanding of association colloids, this work has resulted in a number

of improved experimental devices and techniques applicable to other problems.

Titanium Compounds. In order to provide identical materials

to the many research programs concerning the fundamental

properties of the element titanium, selected compounds of high

purity were prepared. For example, titanium tetrachloride of

99.999 percent purity and titanium tetrabromide of 99.998 percent

purity were furnished in a cooperative program of basic research on the extractive metallurgy of titanium, sponsored by the Office

of Naval Research. Descriptions of methods for purifying and

for testing the purity of the products by cryoscopic, infrared, and

spectrochemical means were published.

In another program involving the study of barium titanate

ceramic dielectrics, sponsored by the Diamond Ordnance Fuze

Laboratories of the Army, barium titanyl oxalate having a ratio

of barium oxide to titanium dioxide of 1.0000 was prepared.

Ignition of this compound produces pure barium titanate of

theoretical composition. Titanium dioxide of high purity, as well as barium carbonate, were also prepared. With these three

compounds, the critical composition of important ceramic dielectrics can be accurately controlled.

Labeled Sugars. Radioactive sugars and related compounds,

with their precisely placed carbon-14 atoms, provide a means for solving many problems in biology, medicine, bacteriology, and

the physical sciences. In fact, they have proved so useful that

there has been an increasing demand for more and differently

labeled sugars, to attack new and specialized problems, especially

those in cancer research. Workers in biological research alone

used 276 of the samples during the current year. Because of the

high cost of C

14-labeled reagents, more efficient methods of synthesis

have been devised under AEC sponsorship that have increased the

1%
Complex jet-engine alloys can be analyzed accurately by using ion-exchange

columns to separate metallic constituents (p. 39). This procedure permits

the quantitative determination of nickel, manganese, cobalt, and iron in the presence of niobium, molybdenum, tantalum, tungsten, silicon, and

copper. yield of D-glucose-l-C14 from 10 to 50 percent; of D-glucose-6-C14 from 15 to 50 percent; of D-arabinose-l-C14 from 3 to 37 percent;

and of glycitols from 65 to 95 percent. Although the work on

these labeled carbohydrates has a practical objective, fundamental

studies of the reactions and their mechanisms have contributed

much to our knowledge of the structure of organic compounds.

To meet the important need for these compounds, the Bureau

will continue to prepare and distribute them to research workers

at cost, until such time as they are available from private industry.

Research in Analytical Chemistry. New techniques, better

methods, and improved instruments help greatly to meet the

demands for higher accuracy now required by research laboratories

and for more complete quality control by industry. A research

staff is therefore required to keep abreast of new developments and

to anticipate new needs because the materials to be analyzed often

contain combinations of the less common elements that have

39
Inert atmosphere chamber used in studying electrodeposition of metals from

nonaqueous media. The chamber permits nitration, distillation, transfer,

and weighing of reactants or products without contamination from water or carbon dioxide.

received little attention. Methods for analyzing industrially important alloys have received much attention; ion-exchange methods

have been developed for separating the constituents of heat-resisting jet engine alloys and for separating the rare earths from one

another; flame photometric methods are now being used for the

rarer alkali metals, such as lithium, in clays and ceramic products;

methods are now available for the difficult separation and determination of chlorides, bromides, and iodides; microchemical

methods have been developed for the analysis of complex polymers

containing fluorine, chlorine, and bromine; and spectroscopic

methods have been developed for the analysis of complex dental

alloys, zinc alloys, and high-speed tool steels. The latter methods

are very rapid and are therefore of special importance in the

manufacture of commercial articles where control of composition

is a deciding factor.

Electrodeposition of Metals from Organic Solutions and Fused

Salts. Many elements have physical and chemical properties that

would make them extremely useful as protective or ornamental

coatings on other metals. However, some of the more promising

40
ones, such as beryllium, aluminum, titanium, zirconium, cannot

be electrodeposited from water solutions. Exploratory work has

indicated that deposits of some of these can be obtained electrolytically from nonaqueous solutions. Methods have been developed for depositing beryllium and alloys of boron with beryllium

and magnesium from organic solutions. Work on electrodeposition

is jointly sponsored by the Department of the Navy, the Department of the Army, the Department of the Air Force, and the

Atomic Energy Commission. Improvements have been made in plating aluminum from organic solvents, and aluminum alloys

containing titanium and zirconium have been obtained. Although

these processes are not of immediate commercial application, they

represent advances that will undoubtedly find special use in future

technology.

During a general investigation of deposition of metals from fused

salt baths it was shown that pure molybdenum may be recovered

from most scrap molybdenum alloys.

Advances in Physical Chemistry. The silver chloride electrode

is one of the most useful reference electrodes for electrochemical

measurements in analytical and physical chemistry. An extended

series of long-needed measurements that provide its standard

electrode potential from 0° to 100° C has been completed. An

advance in the theoretical understanding of the static dielectric

constant of polar liquids was made by a mathematical analysis of

the influence of molecular shape on dielectric constants. Absorption of microwave radiation was detected in the nonpolar gas, carbon dioxide. This discovery is of scientific interest, particularly

in the field of molecular structure. The thermochemical measurement of the heats of formation of

chemical substances is the primary method for precisely measuring

the binding energy in molecules. These data are essential in studying variation of energy content with structure, such as occurs

in isomeric substances and in a homologous series of organic compounds, and in calculating heat balances and reaction equilibrium

constants required by engineers for the design and construction of

chemical process plants. In a project sponsored by the Navy

Bureau of Aeronautics, the Office of Naval Research, and the

Atomic Energy Commission, the heats of formation of several

isomeric heptenes were measured to secure information on the

41
steric effects in hydrocarbon molecules. Measurement of the

heats of formation of titanium tetrachloride and tetrabromide has

provided important information on the thermodynamic properties

of titanium-halogen systems, which are the present basis in the

production of titanium, a metal that is assuming an important role

in industry.

Evaluation of Scientific Data. An important function of the

Bureau is the assembly, tabulation, and critical evaluation of data

in those areas in which science looks to the Bureau for critically

evaluated information in convenient and usable form. Careful

scrutiny of the chemical literature often supplemented by painstaking recalculation of reported values, is required to provide

reliable data. In cooperation with and with the financial support

of the National Research Council, basic data on infrared spectra

relating to about 15,000 compounds are being distributed to more

than 200 cooperating laboratories. Infrared spectra have much

the same value in the identification of chemical substances as fingerprints have in identifying persons. Such data are of great

importance in making analyses, in purifying materials, and often

in establishing the nature and properties of new substances. In

the field of catalysis and adsorbents an annotated bibliography has

been prepared in cooperation with the Bone Char Research Project

under the title "Bibliography of Solid Adsorbents, 1943-53/'

This 1,500-page volume, in press as NBS Circular 566, contains

nearly 14,000 scientific abstracts. Similarly, critical compilations

of dielectric and thermochemical data have been made available.

Special Investigations and Devices. An investigation of the accu- racy and standardizing procedures for instruments that record the

heating values of natural and liquefied petroleum gases has been

completed. With the cooperation of the industries that supply

these gases, this work will contribute to the accuracy of measure- ment of one of the more important commodities of commerce. Developments and use of many chemical compounds have been

retarded because of their reaction with air. Potentially useful

materials that are dangerous or that are altered rapidly in contact

with the atmosphere have remained unexplored and unused.

Devices for separation, purification, transfer, and storage of

poisonous, noxious, or unstable compounds have been developed

through processes that include purification in isolated systems,

42
crystallization or distillation at temperatures far below normal, and

separations based on liquid-solid equilibrium in closed glass vessels or in metallic systems if the reacting materials are corrosive to

glass.

A device developed for the Army Signal Corps occupying only

13 cubic inches and operating on a 11 5-volt power supply maintains

small apparatus at very constant temperatures for an indefinite

time, estimated to be at least 5 years. It depends on the solid to liquid reversible phase changes of stable, extremely pure chemical

compounds. In operation, it quickly attains a temperature of

about 87.5° C with fluctuations not exceeding 0.001° C.

2.6. Mechanics

The Bureau's work in the field of mechanics is concerned with

developing, improving, and maintaining standards for measuring

mechanical quantities over a wide range. These quantities include

sound level power ranging from the threshold of hearing to the

sound experienced near jet aircraft; static pressures from those

present at altitudes up to 500,000 ft above sea level to those

encountered in ordnance work and high pressure industrial processes; relative humidity in the temperature range down to —50° F;

volume capacity from 0.02 cm3 to 2,500 g?X\flow from very low to very high rates in water, gases, and hydrocarbon fuels; weights

from 1/10000000 to 10,000 \b; forces from 1 to 3,000,000 lb; and

vibration amplitudes over the frequency range from 10 to 30,000 cps. Improvements in present mechanical standards and the development of new standards require determinations of numerous constants and properties of materials, such as density, elasticity, and

tensile strength. Furthermore, basic research is required along a broad front dealing with the mechanics of gases, liquids, and solids. Work is under way on the transmission of sound through air and

other gases down to very low pressures, and for frequencies from

the lower limit of the audible range, about 10 cps, to ultrasonic

frequencies measured in millions of cycles per second. Important

advances have been made during the year in understanding the

origin of boundary layer turbulence, which is an important problem in high speed aircraft, in combustion, and wherever gases or

fluids flow along a solid surface. Greater emphasis has been

placed on a study of shock and vibration. The effects of repeated

367607—55 4 43
loads and temperatures have been studied as important factors in determining strength of materials and structures. The basic research program has led to important applications

such as measurement of physical properties of sea water at great

depths with ultrasonic waves and the determination of humidity

at high altitudes with thin humidity-sensitive coatings.

Measurement of Hearing. A puzzling difference between the

standard sound pressures for the threshold of hearing used in this

country and in England has been investigated. Preliminary meas- urements made cooperatively by the National Physical Laboratory

in England and the Bureau show that the English standard sound

pressures at threshold are about 10 decibels less than the American

standard. A more thorough investigation of this difference is under way, sponsored by the Army Surgeon General's Office,

with plans to make measurements on about 100 persons. An

important element in this research program, being carried on at the Audiology Center of Walter Reed Army Hospital, is the

absolute measurement of sound pressures at threshold in the ear

canal. Measurements of the acoustical impedance of bones of the head for about the same number of persons is expected to provide for the first time a standard for bone conduction audiometry. This audiometric technique is of basic importance in a

physician's diagnosis of hearing loss. Such diagnoses have been

hampered for some years by the lack of a suitable standard.

Jet Noise. Noise produced by aircraft jet engines has become

a major problem. The noise can be sufficiently powerful to cause permanent damage to the hearing of a person near a jet engine.

NACA sponsored researches into the physics of the noise generation, and investigations into methods for reducing it, are being

pursued in several laboratories. At the Bureau a technique has

been developed for measuring accurately the total sound power

produced by a jet of gas issuing into air. The technique is being

applied to model jets, and to models of nozzles designed for reducing jet noise.

Architectural Acoustics. The measurement of the physical

properties of acoustical materials has presented for many years a problem that has not yet been completely solved. This problem

is of considerable economic importance; millions of dollars worth

of acoustical materials are manufactured and installed every year.

44
The essence of the technical problem is that measurements by

various laboratories of the sound absorption by acoustical materials do not agree exactly. The lack of agreement apparently

arises from the inability to achieve a random sound field for absorption measurements. Several physical criteria have been

adduced by NBS staff members for ensuring such a field during

absorption measurements. It has been found that a sound field that is random as far as direction of propagation is concerned,

nevertheless exhibits statistical correlation between the sound

pressures at any two points. A measurement of this correlation

for a given sound field enables one to decide whether or not the

sound field is sufficiently random. This should lead to a standard

method for measuring the sound absorbent properties of the

acoustical materials used in architecture.

Measurement on Material Substances with Sound. Sound waves

are used to measure the physical properties of various substances.

One important application is to researches in the sea. Underwater

propagation measurements are frequently made with an acoustic

interferometer. Under the sponsorship of the Office of Naval

Research, a nonreflecting interferometer has been developed in which the sound wave incident upon a transducer is totally absorbed by the electric circuit of the transducer when suitably

adjusted. This makes it possible to obtain a more direct and more

accurate measurement of sound velocity and attenuation in fluids. Analysis of Sound. The resolution of a sound wave into its component frequencies is one of the important basic techniques

for determining what should be done about reducing noise, or how

a communication system should be designed. Laboratory investigations of the analysis of sound are frequently hampered by the

physical limitations of the available instruments for making such

resolutions. For example, an analyzer might be able to single out

a particular component in a complex mixture of different frequencies, but might require an excessively long time. An investigation

of methods for making frequency analyses with physical instruments, sponsored by the Air Force, Navy, and the Atomic Energy

Commission, has disclosed that the accuracy which might be possible in frequency determination, the time required to determine a particular frequency, and the noise inherent in the physical instrument, are not independent. The exact relationship developed

45
Controlled clearance piston gage (right), the new standard for pressures from

50 to 200,000 psi, is used to calibrate a small piston gage (left). shows how the experimenter can trade accuracy of frequency

determination for speed of analysis despite the presence of the

inevitable noise which every physical instrument has.

Measurement of High Pressures. Modern industrial processes

and military weapons are more and more frequently using pressures

above 100,000 pounds per square inch. These high pressures

must be measured under transient or rapidly changing conditions

as well as under very high static pressures. The results of the

NBS program in high-pressure measurement are applicable to both

types of measurement^ and work sponsored by the Aberdeen Prov46
ing Ground is aimed particularly at the problem of providing

adequate standards for calibrating instruments used in such

measurements. During the year attention has been given to improving the NBS controlled-clearance piston gages to increase

precision of measurements at very high pressures. Improvements

were made in the auxiliary equipment necessary in this work,

including the further improvement of electrically insulating seals

to permit multiple electrical connections to be made to the interior

of high-pressure vessels. The development of an essentially

leak-tight movable seal, having relatively low friction, for use in

equipment generating very high pressures was also accomplished.

Serological and Flight Test Instruments. The field of aerological

instrumentation has assumed increased importance, particularly in connection with the operation of high-performance aircraft. In

this work accurate and rapid measurement of water-vapor content

of the atmosphere, including that of the upper air, is required.

Under the sponsorship of the Department of Defense and the

Atomic Energy Commission, an improved instrument using microwave principles has been developed for such measurements. This

instrument depends upon the varying dielectric constant of the

atmosphere as water-vapor content varies, and provides a sensitive

and accurate measure of humidity. In military aircraft flight

testing, increasing attention is being given to telemetering techniques for overcoming the limitations of conventional testing

methods. Under the sponsorship of the Office of Naval Research,

the Air Force, and the Atomic Energy Commission, improved

methods of measuring the characteristics of certain telemetering

instruments have been devised, and work has continued in improving flight test instruments to enable them to meet increasingly severe requirements in testing modern aircraft.

Water-Wave Research. The physical laws governing growth and

decay of water waves, the relation of their amplitude and other

characteristics to the wind producing them, and the forces exerted

by such waves on engineering structures have long been of importance to naval architects in designing ships, and to engineers in

designing shore and harbor structures. Because of the importance

of these problems a continuing program of water-wave research

has been under way for some years at NBS, supported principally

by the Office of Naval Research.

47
Two phases of this investigation, involving an experimental study

of the growth of wind waves in a channel and a theoretical study

of the wind tides on idealized reservoirs of rectangular shape have

recently been completed. These studies have particular application to the design of engineering structures along the shoreline

of lakes located on comparatively flat terrain where the wind

forces may be large and where relatively small tides may inundate

large areas of adjoining land. The results of these studies illu- minate certain aspects of energy transfer from air currents to water waves and tides and provide means for estimating the

magnitude of wind-generated waves and tides. Density Current Research. Salt-water intrusion into the coastal

rivers and navigation canals of the country has in recent years

seriously threatened the water supplies of cities, industries, and

farms located along these rivers. Because of the importance of

this problem, the Army Corps of Engineers has supported an

extensive research program on density-current flow at the Bureau

during the past 6 years. This program has consisted of two principal phases: (1) the density-current flow from a canal lock connecting on one side to a saline body of water and on the other side to a fresh-water channel, and (2) the density-current flow from an ocean into a fresh-water channel.

The results of these investigations, reported to the Corps of

Engineers, include the effect of density difference, river velocity,

depth of channel, length of travel, salt-water barriers, etc., on the

velocity, depth, mixing, interfacial stresses, and other characteristics of the density-current flow. Boundary Layer Transition. An important problem arising from

motion of a body through air or water is the nature of the flow in a thin layer over the surface, called the boundary layer. In general,

the fluid in a boundary layer flows smoothly and orderly (laminar)

for some distance along the surface and then breaks into the chaotic

motions of turbulent flow. Between the two types of flow there

is a transition region in which flow is alternately laminar and

turbulent. Referred to as boundary-layer transition, this phenomenon is of great practical importance. For example, the .speed

and range of both aircraft and missiles are strongly influenced by

the extent to which their surfaces are covered by turbulent flow.

Recently the Bureau concluded one phase of a continuing" experi48
The NBS supersonic wind tunnel produces wind velocities up to twice the

speed of sound. Insert: Closeup of test chamber with hot-wire anemometer

probe in place (p. 48). mental investigation sponsored by the National Advisory Committee for Aeronautics on the fundamental processes of boundarylayer transition. With the hot-wire anemometer as the principal

measuring instrument, studies were made in the boundary iayer

with air flowing along a flat plate. The nature of the transition

region has been clearly defined. It was shown that transition is a process in which turbulent spots first form, then grow as they

move downstream. The rate of propagation, shape, and other

significant features of such turbulent spots have been studied.

These results have provided new insight and have given added

impetus to basic investigations on the mechanics of transition.

Surface Roughness. An important aspect of the transition of

laminar to turbulent flow along the surface of bodies moving

through air or water is the effect of surface roughness. Under the

sponsorship of the National Advisory Committee for Aeronautics,

the effect of 2- and 3-dimensional roughness elements on boundary

layer transition in air flowing past a flat plate was investigated. It was found that there is a marked difference in behavior between

2-dimensional and 3-dimensional roughness. Three-dimensional

roughness has less effect on transition than does the 2-dimensional

49
but is extremely sensitive to changes in wind speed or position in the surface. The data obtained show that rougher surfaces induce

earlier transition. Also, surface roughness must be considered in any attempt to control boundary layer transition by using suction.

Vibration Standards for the Calibration of Pickups. Thousands

of vibration pickups are used by governmental and industrial

laboratories for testing missiles, aircraft, ships, surface vehicles,

and other types of equipment. Major engineering decisions are based upon measurements made with vibration pickups, particularly the endurance of aircraft and other structures. The

successful performance of these structures and the lives of operating

personnel depend upon the accuracy of observations made with the

pickups and therefore on their calibration. To meet this need,

vibration standards have been developed and NBS now offers a limited calibration service for vibration pickups measuring displacement, velocity, or acceleration.

The vibration standard consists of an electrodynamic vibration

exciter and a velocity sensing coil calibrated by the reciprocity

method. This calibration requires measurements of mass, fre- quency, and electrical quantities only, and therefore avoids the

difficulty of measuring accurately the small displacements of

high-frequency vibrations. Between 30 and 900 cps the cali- bration factor of the standard was found to be constant within

1 percent. At higher frequencies the calibration factor is known

with somewhat less accuracy because of undesirable resonances. These resonances change the electromechanical characteristics of

the standard and result in less stability than is present at the lower

frequencies. The method for calibrating pickups involves the

application of a known level of vibration amplitude to the pickup

and the measurement, with a potentiometer circuit, of the ratio of

the pickup output voltage to the output voltage of the velocity

sensing coil. If desired, both the magnitude and phase of the calibration factor can be determined. Pickups calibrated for amplitude only would

be suitable for making many vibration measurements in structures. Pickups calibrated for both amplitude and phase would be suitable

as secondary reference standards for governmental and industrial

laboratories, or for vibration measurement on structures where

great precision is needed.

50
Thermal Stresses. With the advent of high-speed flight, a need

has arisen for a reliable method of predicting stresses and deflec- tions in aircraft structures caused by transient temperature

gradients from aerodynamic and jet-engine heating. The solution

> of the problem is a dual one requiring first the computation of the

transient temperature distribution, and secondly the computation

of thermal stresses and deflections corresponding to the temperature distribution. A study sponsored by the Office of Naval

Research was undertaken to develop procedures for predicting

thermal stresses and deflections and to check these procedures by

tests on simple structures. A numerical method for computing on SEAC the two-dimensional transient conductive heat flow in an I-beam has been

generalized to include prediction of temperature distribution in beams of various cross-sectional shapes, and the effects of radiant

as well as conductive heat transfer.

Analyses were made of simple beams heated from one side only.

Consideration of a large number of cases led to the conclusion that

large variations in temperature distribution and heating rate may

have only moderate effects on thermal stresses and curvatures. Radiant heat transfer between parallel plates of inconel and

aluminum was investigated for a wide range of temperatures and

temperature differences. It was found that using a simple gray

body assumption instead of the actual emissivity of the material

to compute the heat transfer rate resulted in errors from 2 to 29

percent. It was shown that in the absence of convective heating,

radiant heat transfer predominates over conductive heat transfer

for inconel structures and is significant for aluminum structures at elevated temperatures.

Fatigue Strength of Aircraft Structures. Owing to a steady in- crease in maneuvering loads of high-performance military aircraft,

the problem of fatigue failures has become critical. Design data on fatigue strength of aircraft structures are urgently needed. In

response to this need the Navy Bureau of Aeronautics has requested

that fatigue tests be made to provide data on typical structural

components, especially in the high-load range.

Most aircraft structures are so complicated that predicting their

performance under repeated loads from available data on fatigue

strength of materials is quite difficult, if not impossible. The

51
general use of limit loads as criteria for airplane design makes them

a desirable basis for making a plot of stress versus number of cycles

to failure. A test program was initiated to determine the variation

of life with percentage of limit load for 2 types of wing beams

under 2 different loading conditions. Fatigue results of the

various tests were in good agreement.

In order to provide additional data, tests sponsored by the Navy

Bureau of Aeronautics were conducted on 75S-T6 aluminum alloy

specimens machined from hand-forged bars of 75S aluminum alloy.

The stress concentrations used for this work were rectangular lugs

protruding from the minimum cross section of the specimens. The

tests were designed to show the effects of variations in the fillet radius at the base of the lug, the lug height, width, and the mean

stress. The maximum stress was chosen to emphasize fatigue

failure occurring in 10,000 cycles or less. The test results showed

that fatigue strength decreases with decreasing fillet radius and

increasing lug width. Substantial variation in lug height had no

effect on the fatigue strength. Very high stresses reduced the

effect of the stress concentrations. This is believed due to the

increased plastic flow at the stress concentration.

Airplane Design. In determining whether the structure of an

airplane can support the loads that will be imposed upon it during

its lifetime, its structure is analytically evaluated for flight, landing, and takeoff conditions and the prototype undergoes a series of

tests to evaluate its strength. Usually, only those conditions

believed to be most severe are investigated in the analytical evaluation because of the limited time available. By using high-speed

digital computing machines, it has become possible to study a wider variety of conditions and to determine the relative importance

of the different parameters in the configuration of the airplane as

it flies, takes off, or lands.

With the plan of investigating a wider range of parameters than

had previously been included in the analysis, a study was undertaken for the Navy Bureau of Aeronautics to determine the loads on the landing gears of an airplane when it made arrested landings on an aircraft carrier. By varying each of the landing conditions

in turn while keeping others constant, initial landing conditions

resulting in maximum loads on the landing gears were found. This

study indicated which of the initial conditions should govern the

52
Thousand-pound balance developed for use by State weights and measures

groups. Apparatus conveniently weighs a 1,000-lb weight with an accuracy

of about one part in a million. design of the landing gears and also over what range the pilot could

safely vary his sinking speed, engaging speed, wing lift, and

pitching velocity as he brings his plane in for a carrier landing.

Faced with the problem of providing room for fuel tanks or other

stores in the airplane wing, or decreasing the over-all weight of the

airplane, a designer might eliminate some of the wing ribs or reduce

their stiffness. To answer the question of whether either of these

alternatives may lead to serious vibration in flight, the vibration

modes of several wings were determined. A delta wing was chosen

as basic. The vibration frequencies and modes were computed

for the basic wing and for several modifications of the basic wing.

Results showed that the frequencies and mode shapes of modified

wings differed little from those of the basic wing and, therefore,

that the modifications would not appreciably affect vibration

characteristics of the delta wing.

One Thousand-Pound Balance. A balance that can weigh a

1 ,000-lb weight with an accuracy of about one part in 1,000,000 was

53
constructed. The balance was designed with special pickup attachments to make it convenient in laboratories handling large weights.

Although the balance was developed especially for use by State

Weights and Measures groups, it will be of interest to many

industrial laboratories. Working drawings of the balance have

been made available to balance and scale manufacturers.

Densities of Alcohol-Water Mixtures. It is known that alcoholwater mixtures provide additional thrust for jet aircraft takeoffs.

Both ethyl alcohol and methyl alcohol are used. The proportions

of alcohol to water for maximum thrust increase are limited to rather narrow ranges, different for each of the two alcohols. The

approximate proportions are to be checked in the field with a hydrometer. To provide a basis for these field checks, the Air

Force has sponsored a series of density determinations to derive a relation between specific gravity, temperature, and concentration

of the mixture. The first density determinations were made on methyl alcohol-water mixtures.

Combustion in High-Velocity Air. Preliminary studies under

sponsorship of the Navy Bureau of Aeronautics on gaseous oxygen

injection in ramjets and reheaters showed enough promise to warrant further study in reheaters only. A development and

testing program sponsored by the Wright Air Development Center on ceramics and metal ceramics for jet engine components has

been completed and specimens have been prepared for WADC to

test in full-scale engines.

Fuel Accessoriesfor Aircraft. Having aided the military services

adopt standard fluids for testing and setting reciprocating engine

carburetors and gas-turbine fuel-control units, the Bureau has

begun to specify fuel control settings for test equipment of the

Navy. Test equipment at approximately half of Navy's overhaul

stations has been adjusted by NBS personnel so that test results

agree with those obtained at the Bureau. These correlation

programs are continuing. During the year calibration facilities for fuel flowmeters were set up with an accuracy of 0.2 percent over

the flow range from 4 to 100,000 lb/hr. Eight master regulator

units have been built for use at Navy stations to check the relia- bility of their carburetor flow benches. This work has been

sponsored by the Navy Bureau of Aeronautics.

54
2.7. Organic and Fibrous Materials

The Bureau undertakes a wide range of basic and applied

research on natural and synthetic polymeric materials, including

rubber, textiles, paper, leather, and plastics. All of these materials

are composed of very long, chainlike molecules formed by the

process of polymerization. Many of their useful properties depend

upon the size, shape, distribution, and flexibility of the molecules

and interaction with other molecules. The mechanisms involved

in forming polymers, their constitution, structure, and properties

are being investigated to advance fundamental knowledge of these

industrially important materials.

Basic research during the year included studies of crystallization

and melting phenomena in polymers, the propagation of stresses and strains in fibers, the structure of polymers, stability of polymeric materials in relation to their chemical structure, dielectric

relaxation times, and molecular properties of polymers used as blood plasma expanders.

Representative applied research projects were concerned with

rain erosion of aircraft surfaces, laboratory methods for estimating

permanence of record papers, the development of polymers for

high temperature use, a method for measuring infrared absorption

of insoluble materials, a method for measuring the temperature of

air in a tire while the tire is operating, and improvements in dental

materials and processes. Several statistical procedures of value to the polymer technologist were also developed and published.

Crystallization Phenomena in Polymers. In a program sponsored

by the Office of Naval Research, the thermodynamics of natural

rubber and guttapercha crystallization were investigated, the exist- ence of equilibrium melting temperatures was established, and the

thermodynamic parameters governing the crystallization were

determined. The high melting point and other unusual crystallization features of stark rubber, a variety of natural rubber, were

found to result from the preferred orientation of its crystallites.

The orientation was described by a pole figure analysis using X-ray

diffraction techniques. Based upon these results, methods were

developed for preparing stark rubber in the laboratory.

In view of the use of butadiene as one of the major constituents

in GR-S synthetic rubber, the melting behavior of polybutadienes

prepared at different temperatures was studied. The melting tem55
Apparatus used at NBS to obtain a more complete understanding of stark rubber (p. 55). peratures were found to be appreciably higher than expected and

to depend on the proportion of the polymer in the trans 1,4 configuration.

Behavior of "Pure Gum" Rubber Vulcanizates in Tension. Finding a single parameter to define the stress-strain properties of a given rubber would help in studying vulcanization kinetics. Such

a parameter has been sought in work sponsored at the Bureau by

the Office of Synthetic Rubber of the Reconstruction Finance

Corporation. The most obvious choice is Young's modulus, the

slope of the stress-strain curve at the origin. Indeed, for pure

gum rubber vulcanizates in tension for a fixed time, it has been

found possible to express the ratio of stress to Young's modulus

in terms of a specific function of the elongation. The elongation

function can be applied to natural rubber and to the common

synthetic rubbers GR-S, GR-I, and Neoprene, but not to vulcanizates of these rubbers containing carbon black. The same

function was found applicable to various fixed times of creep

between 1 and 10,000 minutes, and the amount of creep, in the

absence of degradation, was found to be approximately linear with

the logarithm of the time. In order to avoid effects associated

with crystallization, elongations were limited to values less than

56
200 percent. Using this normalized function, one can obtain a value of Young's modulus for any specified time of creep from a

single observation of stress and strain.

Effect of Atmospheric Contaminants on Textiles. The effect of

dinitrogen tetroxide, an atmospheric contaminant, on textiles was

studied with the aid of equipment specially developed for the

purpose. In this equipment the textile is exposed to a stream of

air of specified temperature, relative humidity, and concentration

of contaminant. Dinitrogen tetroxide in concentrations of the

order present in smog and in certain industrial areas causes deterioration of cellulosic textiles. Fabrics made of cellulose fiber,

cotton, ramie, and commercially deacetylated acetate were found

to be equal in resistance to air containing dinitrogen tetroxide.

However, they were less resistant than viscose rayon fabric. Both

partial cyanoethylation and partial acetylation increased the re- sistance of cotton fabrics to dinitrogen tetroxide.

Effects of Light on Coated Groundwood Papers. It has been found

in recent research that clay coatings on papers containing groundwood fibers afford partial protection against deterioration by light.

The fact that exposure to light changes the color of groundwood

paper can be readily observed by placing a partially covered sheet

of newsprint in sunlight for a few hours and then comparing the

colors of the exposed and covered portions. Because coated groundwood printing papers are being used in growing quantities, it is of

interest to the Government as well as to other users of paper to know how much protection against light is given by the coating.

Both clay-coated groundwood papers and some from which the

coating had been removed were irradiated by a carbon-arc lamp

with a cupric chloride filter so as to simulate skylight filtered

through window glass. Uncoated groundwood, chemical wood,

and rag papers were similarly irradiated for comparison. The

effect was measured by changes in alpha-cellulose content and

reflectance of blue light. Results showed that the coating offers partial protection against light; the coated groundwood papers

showed greater deterioration than those not containing groundwood, but much less than uncoated groundwood papers or those

from which the coating had been removed. Laboratory aging

tests using heat alone showed that groundwood papers are quite

stable under applied heat.

57
Accelerated Aging of Record Papers. A quick and reliable

laboratory method for estimating relative permanence of record

papers is important for large users of such papers, both to determine

the quality of record papers they buy and to assess the probable

value of new types of papers. Accelerated aging of paper by

heating for 72 hours at 100° C has been used as a test for many

years. In 1928 the Bureau tested a series of commercial writing

papers before and after aging under these conditions, and stored

specimens of the paper for future testing. Chemical tests were made after 4, 8, and 22 years of natural aging, and physical tests after 4, 8, and 26 years. A fair correlation between accelerated

and natural aging was found for changes in alpha cellulose, copper

number, total acidity, and folding endurance. Results of chemical

tests on rag papers showed very little change in 22 years, whereas

the folding endurance decreased to half its original value. Therefore a distinction must be made between the permanence of the

cellulose fibers and that of the properties of the paper sheet.

Amino Acid Analysis of Collagen. In recent years increased

emphasis has been placed on the fundamental structure of fibrous

proteins, such as collagen. In addition to the importance of

collagen in leathermaking, recognition of the important role it serves in the various connective tissues of the body has greatly

intensified the interest of medical science. Electron microscope,

low- and high-angle X-ray diffraction, and similar measurements

have resulted in a number of proposed structural formulas for collagen. Ultimate proof of the structure still resides, however,

in amino acid analysis.

Progress in unraveling the structure of collagen has been retarded

in the past by the time-consuming, laborious methods of amino acid

analysis. For this reason, efforts at the Bureau have been di- rected toward a more rapid means of determining the amino acid

content of collagen. A two-dimensional paper chromatographic

technique has been developed which will permit an accurate analysis of 17 of the 18 amino acids found in collagen in 4 days. A complete amino acid analysis of purified collagen by this rapid procedure

confirmed values generally accepted for the protein. This is one

of the few analyses in which all the amino acids have been estimated

from the same initial collagen sample.

58
These electron micrographs, revealing the presence of large numbers of extremely small pores, may provide new insight into the structure and be- havior of leather. Micrographs show disrupted collagen fibrils of kangaroo

tail tendon dispersed in water. This technique should encourage more studies on the amino

acid contents of proteins. As a means of following the course of a chemical reaction, it should produce more precise information on

degradation of proteins. A study has been completed on the re- action between nitrous acid and collagen in which the paper

chromatographic method was used as an analytical tool for analysis

of the products.

Micropore Structure of Leather. Many of the unique properties

of collagen and the tanned product, leather, are believed to result

directly from the character of the collagen that is formed in nature

as a fibrous network. For example, the remarkable resistance of

leather to flexural fatigue may be attributed to the ability of the

367607—55 5 59
individual fibers to reorient under stress. Similarly, the per- meability of leather to water vapor, which makes it well suited

to use in footwear, is related to the presence of pores. Pressure porosimeter and electron microscope studies completed

during the year are expected to provide new insight into the

structure and behavior of leather. This work revealed the presence

of large numbers of extremely small pores—less than a millionth of an inch in radius—in both leather and its parent substance,

collagen. The quantitative information obtained on pore-sizes

distribution within the individual collagen fibrils will aid the

leather technologist in understanding the swelling and shrinkage

accompanying water-leather interactions. It is also shedding

additional light on the ability of leather to transmit or absorb

water vapor, tannins, or impregnants.

Temperature of Tires. The temperature of a tire while operating

is an important factor affecting the rate of deterioration. Although

many measurements of temperature have been made, there is no

published information on the reliability of such measurements.

This past year a study was completed on the temperatures en- countered at different locations within the inner tube while the tire

is operating. The study resulted in a reliable procedure for

obtaining the average temperature of the air within a tire. This

work was sponsored by the Office of Synthetic Rubber of the

Reconstruction Finance Corporation.

High-Temperature Polymers. A great need exists in the military

services for materials having low dielectric loss and at the same

time a high thermal stability. Often such materials must be

subjected to temperatures as high as 525° C or even higher.

Under sponsorship of the Army Ordnance Corps, the Bureau is attempting to develop such a material by two different methods

of attack. The first is to synthesize polymers having certain structures that are likely to resist thermal decomposition at these

higher temperatures. In the second method attempts are being

made to improve the thermal stability of existing materials. To

this end samples of polytetrafluorethylene have been subjected to high temperatures under various gases. It has been found that some gases, e. g., nitrogen, have no effect on the rate of decomposition; others, such as water and oxygen, have an accelerating

effect; while still others, such as chlorine, hydrogen, and fluorine,

60
In this apparatus, tagged expanders are converted to carbon dioxide for measurement in an ionization chamber. Insert: Molecular weight data on

blood plasma expanders are obtained by measuring their osmotic pressures. markedly inhibit the rate of decomposition. When the most

suitable gases for improving thermal stability are determined, they

will be incorporated into the polymers as solid compounds that

give off these gases at high temperatures.

Blood Plasma Expanders. In cooperation with the Office of the

Surgeon General, Department of the Army, and the National

Research Council, the Bureau continued its study of the molecular

properties of polymers that are being used as blood plasma volume

expanders. Clinical tests have shown that the most commonly

used plasma substitute, dextran, has a tendency to cause an

increased bleeding time in patients who have the material infused

into their blood. The hypothesis has been advanced that this

adverse effect may be caused by sorption of the dextran molecules

to body tissues or to the surfaces of the blood-clotting agents

(platelets) in the blood. A preliminary study of the sorption of

dextran to collodion membranes was made using dextrans labeled

with carbon-14. The amount of radioactivity remaining on the

membranes after exposure to the dextran solutions is a measure of

the degree of sorption. It was demonstrated that sorption

actually did take place and also that the presence of surface-active
agents had an effect on the amount of dextran adsorbed. Later

investigations, also employing the carbon14-labeled dextrans,

showed that sorption of dextran also takes place on platelets

obtained from human blood. It has not yet been determined,

however, that this adsorption is the cause of the excessive bleeding:

previously mentioned.

Dielectric Studies. Almost all polar organic substances, whether

crystalline or liquid, exhibit evidence of a spectrum of dielectric

relaxation times. A theory which begins with molecular considerations and leads to such a spectrum for polar organic crystals

has been developed. Each of the dielectric relaxation times comprising the spectrum is the negative reciprocal of one of the eigenvalues of a simple matrix. The theory leads to predictions that

are qualitatively correct, but a quantitative application has not

yet been attempted.

Multiaxial Stretching of Plastic Glazing Material. Polymethyl

methacrylate plastic sheet is used in canopies and windows for

aircraft. When subjected to tensile stress for various periods of

time, this material develops fine cracks, known as "crazing," and

must then be replaced. The Bureau has been studying this

problem for some time under the sponsorship of the National

Advisory Committee for Aeronautics. In 1952 it was shown that

by multiaxially stretching polymethyl methacrylate sheet, the

resistance to crazing is greatly increased. In addition, a laminar

structure is produced which results in greatly increased strength.

Several new or modified transparent plastics offering increased

heat resistance have recently been produced. These materials

include modified polymethyl methacrylate and polymethyl alphachloro-acrylate. The effects of multiaxial stretching on the

properties of these plastics has been investigated. This work

showed that the craze resistance of these materials is also greatly

increased by stretching, with a similar laminar structure resulting.

Thus these new transparent plastics offer great promise for use in stretched form for aircraft glazing, with increased heat resistance over the plastic glazing now in use. Infrared Spectra of Insoluble Organic Materials. The infrared

spectra of insoluble materials can be obtained by embedding the

materials in a potassium bromide pellet which serves as the analytical specimen. This potassium bromide pellet technique is suitable

62
Photographic studies are providing a better understanding of the mechanism

of rain erosion of aircraft surfaces (p. 63). Left: Starch-iodide trace of radial flow of waterdrop. Right: High-speed moving pictures of the collision and flow of a water drop. for materials that have a very fine particle size, i. e., 1 to 5 microns

in diameter. Some materials cannot, however, be powdered to

this size, and others cannot be pulverized without deterioration

of the material. By embedding materials to be studied in a matrix

having a refractive index comparable to that of the material under

examination, it was shown that particles as large as 110 microns

in diameter can be measured. Most polymeric substances have a

refractive index between 1.47 and 1.6 n^°. Potassium chloride,

sodium chloride, potassium bromide, and potassium iodide repre- sent a series of matrices that can be used to cover this range. The

infrared spectra of insoluble resins, paper, and textile fibers have

been obtained by this technique.

Mechanism of Rain Erosion. One of the problems accompanying

the development of high-speed aircraft is erosion of the surfaces of

the leading edge and of the radar housings, which results from

flying through rain. Work toward an understanding of the

63
mechanism of this type of erosion was initiated at NBS in 1952 by

the Navy Bureau of Aeronautics and has since been sponsored by

Wright Air Development Center.

Basic information on the effect of a collision of a solid with a more or less spherical mass of liquid has been obtained. The

waterdrop is the tool in this erosion process. At high striking

velocities, a waterdrop acts as though it were a hard sphere, but

unlike a sphere of hard material, it undergoes a radial flow of very

high velocity. The damage done to a given material by collision

with a waterdrop at high speed is caused by impact pressure and

by the shearing action of the radial flow of the drop or the torque

that this flow exerts against protruding irregularities of the surface.

Response of a material to stresses, that collision with a waterdrop

imposes, depends on its own characteristic properties. Hence,

there are as many erosion mechanisms as there are broad groups

of properties in structural materials.

Panographic Dental X-ray Machine. The Bureau cooperated

with the Air Force Dental Service in the design and construction

of a panographic X-ray machine that rapidly takes an X-ray pic- ture of the entire dental arch. This machine will permit a considerable saving in time over present techniques in which up to 14 small films are used for a full-mouth survey.

In the panographic machine, the film is placed outside the

mouth and is exposed by passing a narrow beam of X-rays through

the patient's head from the rear. Movement of the X-ray source and the film is so coordinated that only those structures of the

dental arch desired in the finished film are projected, while other

overlying structures are not. Preliminary experimental exposures

have been made on human skulls and a limited number of live

subjects. Results indicate that the method may be capable of

producing panoramic full-mouth exposures in about 40 seconds,

exclusive of processing time.

It is expected that much time and effort may be saved in making

mass radiographic surveys by this method, and at the same time, more comprehensive and inclusive radiographs will be produced,

giving more information than conventional full-mouth radiographic

surveys. In addition to its usefulness to the armed services, the

equipment has potential application in many other fields where

large numbers of people are examined for dental defects.

64
Gallium Alloys. Gallium alloys were investigated as tooth-filling

materials in a program of dental research conducted by the Bureau

in cooperation with the American Dental Association, the armed

services, and the Veterans Administration. Because gallium melts

at 29.8° C, it can be mixed with powdered metals or alloys by

essentially the same techniques as are used to mix mercury with

silver alloys to form the amalgams commonly used for restoring

teeth. Gallium's ability to wet many materials, including tooth

structures, should give good adaptation when a gallium alloy is condensed into a cavity.

Results indicated that face-centered cubic metals such as gold,

nickel, copper, and some intermetallic compounds of copper and

tin when mixed with gallium do produce alloys which harden at room or mouth temperature. Data obtained on a gallium-nickelsilicon alloy do not show the decrease in strength found in amalgam

alloys heated to the elevated temperatures normally encountered

in the mouth. Also, the gallium alloys appear to have better

tarnish resistance than does dental amalgam. One disadvantage

of the gallium alloys is their relatively high setting expansion

(50 microns per centimeter or greater). Data obtained indicate

that it may be possible, however, to reduce this expansion some- what by adding small amounts of cobalt, silicon, or other elements.

Some of the gallium alloys appear to have properties equal or superior to dental amalgam, but clinical evaluation will be neces- sary before any of them can be recommended for dental use.

2.8. Metallurgy

The Bureau's work in physical metallurgy is concerned with the

melting, fabrication, and heat treatment of metals and alloys; and

with determinations of metal structure, properties, and behavior

under normal and unusual conditions of service. In general, this

program is directed toward increasing both theoretical and practical knowledge in order that new or improved metals and alloys

may be developed for better, safer, and longer performance in present uses and to meet requirements of new applications.

Constitution Diagrams. Accurate and detailed diagrams that

show the melting points, structural changes occurring at various

temperatures, intermetallic compounds, and solubility relationships are of vital importance in understanding the behavior and

making the best use of metallic alloys. The use of iron-chromium65
nickel-molybdenum stainless steels in turbine buckets, aircraft

parts, and automobile engine valves is limited, probably because

of structural changes induced by the very high temperatures in which such parts operate. To obtain more information on this

subject approximately 100 alloys were prepared and portions of

each were exposed for long times to temperatures between 1,500°

and 2,200° F. Metallographic and X-ray diffraction studies of

these specimens permitted the construction of diagrams that show

the temperature range of existence and solubility relationships of

various phases, including two new intermetallic compounds. These

are similar to the previously identified brittle sigma phase. The

diagrams show the operating conditions that should be avoided to prevent forming these undesirable constituents.

Work on the binary diagrams of magnesium with lanthanide

(rare earth) metals was begun under the sponsorship of Wright

Air Development Center. Additions of mixed lanthanide elements

improve the strength and stiffness of magnesium at high temperatures for applications in modern high-speed aircraft. Development of accurate binary diagrams should help to explain this effect and should indicate the possibilities of further improvement. The

establishment of binary diagrams of interest to the Atomic Energy

Commission was continued.

Properties and Behavior of Alloys. The effect of a few thousandths of 1 percent of boron, in promoting the hardenability of

steel that is quenched after heat treatment, has been established,

but the accompanying effect of boron on other properties of the

steel is not well known. The popular low-alloy chromium-nickelmanganese steels of the 81xx series can be heat treated to desirable

hardness and strengths, particularly when boron is added, but this

improvement in some properties may be accompanied by a decrease

either in ductility or in resistance to impact. Under the sponsorship of Watertown Arsenal, an investigation of the effect of boron

additions on the impact properties of slack-quenched-and-tempered

steels is in progress. Experimental steels were made and heat

treated, and the testing program is under way. Another phase of

the problem was initiated late in the year, at the request of Wright

Air Development Center, to investigate the effect of boron additions, alone and with other elements, on the susceptibility of 8140

steel to temper embrittlement.

66
A fatigue crack starting on the inside of the hollow steel blade caused the

failure of this aircraft propeller. NBS examination showed that the crack

resulted from a gouge made bv a mandrel during the blade's fabrication

(p. 69). Tensile strengths of 300,000 pounds per square inch have been

obtained bv appropriate heat-treatment of low-allov steels, for example, type 4340, but optimum use of these high strengths in structures cannot be made until means can be found to improve

ductility. Under the sponsorship of the Navy Bureau of Aeronautics, experimental steels of slightly modified 4340 composition were prepared, heat treated to 300,000 psi tensile strength, and

were subjected to tests. The best of the experimental steels, which

will be studied further, has about 10 percent elongation at room

temperature, and about 15 foot-pounds impact strength at —50° C.

Mechanism of the Deformation of Metals. Metals under applied

stress may be subject to elastic or plastic deformation, or both.

Elastic deformation occurs under short-time application of rela- tively light loads, and the metal recovers completely when the

load is removed. Plastic deformation involves permanent changes

in the metal and occurs under heavier loads and longer times of

load application or at higher temperatures. In an attempt to determine the mechanism of such deformation, particularly in the

transition range where plastic deformation begins, polycrystalline

rods and coarsely crystalline specimens are being studied by X-ray

diffraction and metallographic techniques. The purpose is to identify the effects of intergranular stresses, dislocations, grain

boundary migrations, and misorientations in lattice structure. Studies show that changes in Young's modulus under applied stress are different in different directions in both polycrystalline rods

and in individual crystals. In a continuing investigation of the flow and fracture of nickelcopper alloys at elevated temperatures, a study of the creep characteristics of nickel was completed and published. Determinations

were made of the short-time tensile and creep behavior of 70:30

and 30:70 nickel-copper alloys at elevated temperatures.

67
Results of an NBS study shows how some soils damaged unprotected steel pipe specimens during 14 years' exposure. Underground and other types of corrosion cost the United States billions of dollars annually (p. 70). Another aspect of metal deformation and fracture in service is the loss of ductility of many types of steel at low temperatures.

Such brittle fracture in normally ductile steel has received particular attention in connection with cracks and failures in all-welded

ships, but has also been found in other types of structures. The

Bureau's study of plates from ships that had suffered actual cracks

or fractures in service was concluded during the year. Effects

of variations in composition within the limits of specification

requirements had previously been established and it had been

shown that the tendency for cracks to form and propagate could

be predicted from determinations of the transition temperature in impact or tensile tests. There was evidence, however, that the

final answers would require more complete and detailed information about the production of individual plates than was available

from the service failures. To fill this need a project was begun

under joint sponsorship of the Ship Structure Committee and

American Iron and Steel Institute to study material from current

production of ship plate. Plans were made on a statistical basis

for selecting plates and specimens to show variations within a

single plate, in plates from different portions of the same or different

ingots from the same heat, or from different heats. Some of the

materials selected at the mills have been received and the experimental program is under way.

Many years of experience in determining the causes of failures of

metals and alloys in service, particularly in transportation equip68
mentj were summarized in an NBS publication, Circular 550. A

revision of this publication was prepared, by request, for inclusion

in the forthcoming outside publication, Engineering Materials

Handbook.

Titanium. The high strength-weight characteristics of the

"wonder metal," titanium, have not been fully used because of

uncertainty about its performance in other respects. Work at the

Bureau sponsored in part by Wright Air Development Center

showed that the tensile and impact properties of commercially pure

titanium at temperatures from +300° to — 196° C, were sensitive

to the presence of notches or imperfections in the surface, and that

this notch-sensitivity increased as the temperature was lowered.

Differences in the notch-sensitivity of different lots of commercially

pure titanium w

T ere correlated with differences in the content of

interstitial elements, particularly oxygen.

Fatigue of Metals. Under the sponsorship of the National

Advisory Committee for Aeronautics, an investigation is in progress to determine the initial stages of fatigue cracking of

aluminum alloys and to explain why the yield strength of one aluminum alloy (75S) is 25 percent greater than that of another

(24S) even though the fatigue characteristics of the two alloys are almost identical. Large-grained aluminum alloys were subjected

to uniaxial fatigue stresses, with photomicrographic recording to detect the first appearance of cracks in the surface. Most of the

cracks started, not in grain boundaries, but within a grain on the

slip plane that had the largest resolved shear stress. This shows

that decreased resistance from plastic deformation within the

grain is a more important factor than stress concentration from

inhomogeneous deformation at the grain boundary.

The fatigue properties of steel wire and of steel-wire springs are being studied under the sponsorship of Springfield Arsenal. During

the year, a comparison was made of the fatigue properties of wire

drawn from steel of commercial origin and from steel that had been

specially prepared by vacuum melting. It was found that the

material reduction of inclusions and impurities in the vacuummelted steel improved the fatigue properties slightly. To aid in studies of fatigue under torsional stresses, a testing machine small

enough to be mounted on the stage of a microscope was constructed.

69
These exposure racks are used in corrosion-resistance studies for aluminum

alloy specimens. Useful information concerning the effect of a marine

atmosphere on such material has been obtained over a 20-year period (p. 71).

Corrosion. Corrosion of metals costs the United States economy

billions of dollars annually. The Bureau's contribution to this

problem consists principally of attempts to determine the fundamental causes of corrosion and includes sponsored studies of the

corrosion resistance of specific alloys and types of alloys.

Continued studies of the corrosion of monocrystalline aluminum,

in acids and alkalies, have shown that the rate and pattern of the

corrosive attack differ with the crystallographic orientation of the

exposed surface and with the corrodent. Some of the results are being prepared for publication and current activities are directed

to a study of the initial corrosive reactions and the location of the

first corrosive attack with reference to the crystallographic orientation and structural imperfections and irregularities.

The possibilities of electrical measurement for studying corrosion

reactions in progress, and the clarification of the complicated

circuitry, are being studied. Two publications were issued during

the year, one on geometric factors in electrical measurements, the

other on the measurement of corrosion rates by polarization

characteristics.

The application of stress to a corroding metal increases the rate and sometimes changes the nature of the corroding attack, and

frequently generates an attack that would not occur at all in the

70
absence of either stress or the corroding medium. Current studies

include attempts to determine why the stress-corrosion of beta

brass follows a transcrystalline path, whereas in alpha brass the

cracks are intercrystalline, i. e., in the grain boundaries. In a study of the stress-corrosion of type 304 stainless steel, sponsored

by the Welding Research Council, a satisfactorily reproducible,

short-time procedure to produce stress-corrosion cracks has been

developed and work was begun to determine the effect of structural

characteristics and minor variations in composition on the stress corrosion of this material.

The continuing program of exposure tests in marine atmospheres,

sponsored by the Bureau of Aeronautics, includes studies of various

metals used in aircraft construction and of surface or protective

coatings, heat treatment, and methods of fabrication and assembly.

A 20-year study of the behavior of several types of aluminum

alloys was completed and the results were published. Four new

phases of the work were initiated during the year.

2.9. Mineral Products

The Bureau conducts both fundamental and applied research on

a wide variety of inorganic materials. These materials are of

interest in the ceramic sciences and in the nonmetallic mineral

industries because of their use in the production of refractories,

porcelains, pottery, cements, glazes, glasses, and enamels. The

primary objective of this work is the accumulation of basic data on their properties and behavior in order that such materials may

be better utilized. Particular emphasis is placed on broad areas of fundamental research which, because of their nature, are not

likely to receive adequate attention in academic or industrial

laboratories. Examples include investigation of phase equilibria

of inorganic systems, accumulation of thermochemical data, determination of constitution and microstructure of crystalline and

noncrystalline materials, preparation of standard X-ray diffraction

patterns, and compilation of basic data on the physical and chemical properties of inorganic nonmetallic substances.

The demand for materials that are stable at the very high temperatures in atomic power plants, high-speed military missiles, and

aircraft has led to an increased interest in the inorganic materials

that are stable at temperatures well above the working range of

71
the most refractory of metals. Because of the serious lack of

basic data on the properties and behavior of such materials at very high temperatures, the Bureau has placed increased emphasis on accumulation of data acquired for technological advances in these new fields. Recent investigations in this area have been

concerned with study of the mechanisms of creep in single and

polycrystalline materials at high temperatures, properties of ura- nium oxide systems at temperatures of 2,000° C and above, diffusion of gases in glasses, high-temperature protective coatings for metals, phase equilibrium studies of refractory materials, and

mechanisms of thermal decomposition of inorganic materials.

Thermal Decomposition of Crystalline Materials. A continuing

basic study of the thermal decomposition of crystalline solids has

been for the past year primarily concerned with the carbonates

because of their many industrial applications. The thermal decomposition of manganous and ferrous carbonates is complicated

by the several valence changes which these metals undergo at elevated temperatures. The thermal curves of these materials

are greatly modified by such conditions as rate of heating, size of

sample, porosity of the sample holder, and the nature of the sur- rounding atmosphere. Because of these variations it has not been

possible to obtain agreement on the steps through which these

materials passed on heating. However, an investigation carried

out at NBS combining the use of high-temperature X-ray diffraction, an automatic recording thermal balance, differential thermal

curves, and controlled atmospheres, has determined precisely the

equilibrium conditions at different temperatures in air, carbon

dioxide, and inert gases. From this study it is possible to account

for the wide variations in the data obtained by workers in the

past and to predict the results that will be obtained under a variety

of conditions.

Structure and Properties of Glass. The increasing use of glass as an engineering material requires an accurate knowledge of its intimate structure. Information on the changes in structure that occur with changes in composition, fabrication and heat treatment

is also important. Basic studies of the physical, chemical, and

mechanical properties of simple glasses of different compositions

and structures have been continued. The elastic moduli of a

series of glasses have been measured by a dynamic (resonance)

72
method at both room and elevated temperatures. The data

obtained by these measurements have proven more sensitive as an indicator of equilibrium conditions in glass than either density

or index of refraction. The information is particularly useful in the development of heat treatment procedures, of annealing

schedules for glass, and of discovering glass compositions of very

high moduli for the production of glass fibers. Studies of the viscosity, surface tension, compressibility, density,

coefficient of expansion, and electrical conductivity of glasses were

extended to include glasses of the binary alkaline earth borate

systems and the same systems with the addition of 3 mole percent

of potassium oxide. Data obtained in these investigations have

been useful in bringing about a better understanding of structure

of simple glasses of different compositions.

Ceramic Transducers. The Bureau has developed for the Office

of Ordnance Research a number of piezoelectric ceramic compositions that are characterized by abrupt changes in their solid solution structures when their compositions are varied. Such ceramic

transducers have high mechanical efficiency over a wide temperature range. One example is the mole composition 45 PbTi03 :55

PbZr03. Other examples were discovered in the systems lead

titanate-lead stannate, lead titanate-lead hafnate, and lead titanatelead zirconate-lead stannate. The chief figure of merit of a piezoelectric ceramic is the radial

coupling coefficient. For the well-known ceramic piezoelectric

barium titanate, the average coefficient is about 0.35 in the working

range 20° to 80° C. This value can be compared with an average

coefficient of 0.35 ±0.5 over the temperature range 25° to 225° C

for the mole composition 47.25 PbTi03 : 42.75 PbZr03

: 10.0PbSnO3. Similarly, the coefficient ranges from 0.38 at 25° C to 0.31 at 250° C

for specimens made from equal parts of lead titanate and lead

hafnate.

Ceramics Containing Uranium Dioxide. A knowledge of the

high-temperature reactions of uranium dioxide with other refractory materials is essential to nuclear reactor design at higher

temperatures than those found in reactors now in operation. The

high-temperature reactions of uranium dioxide with 15 metal

oxides were surveyed for the Atomic Energy Commission. The

information is based on data established at the Bureau and taken

73
Left: Miniaturized furnace and automatic loading device for transverse

testing of uranium oxide at elevated temperatures in controlled atmospheres.

Four different size fractions of high-purity fused U02 have been measured at elevated temperatures in this furnace (p. 73). Right: Interior of furnace. from the literature. Uranium dioxide forms no compounds or

solid solutions with either alumina, beryllia, or silica. Five of

the binary systems studied show extensive or complete solid

solution.

Physical properties of urania made from four different size fractions of high-purity fused U02 have been measured at both

ordinary and elevated temperatures. Flexural strength ranged

from 8,000 to 12,000 pounds per square inch at room temperature,

and was appreciably higher at 1,000° C for specimens made from

the two finer fractions. Results of the investigation show that

urania for the fabrication of useful shapes should not be coarser than about 5 microns.

Mechanism of Deformation in Ceramics. Under the sponsorship

of the Wright Air Development Center, the study of plastic deformation in ceramic-oxide single crystals has been extended to polycrystalline bodies. Creep rates of such polycrystalline materials as alumina at 1,000° to 1,200° C, and magnesia at 1,200° C,

have been investigated. Both of these materials deform under

constant load. The alumina shows strong creep recovery and as much as one-half the strain is recovered in 10 hours after the load

is removed. However, magnesia shows very slight creep recovery.

These results agree with previous findings that showed that

alumina can slip only on one plane and magnesia can slip on many.

74
The Bureau has devised a new method for determining the

creep yield tensile stress. In the new method, comparatively

simple bending tests replace the former tensile tests on small

specimens which are difficult to test in tension at high temperatures. However, time dependent plastic deformation affects the

determination of creep yield stress and the mathematical treat- ment of the data presents a difficult problem. A method of stress analysis has been developed that corrects the results of bending

tests to give the true value of creep yield stress in tension.

Electrical Conductance in Vitreous Ceramics. As one phase of a broad study of the viterous state, NBS has been investigating the

basic mechanisms controlling electrical conduction in vitreous

ceramic materials. The results have immediate practical signifi- cance because of the need for electrically insulating materials that can be used as coatings on wires and electronic instrument components at high temperatures. This task has included a study of

electrical conductivity in ternary silicates and ternary lead ger- manates. An anaylsis of conductivity data obtained on these

two ternary systems shows that the results can be interpreted in terms of the physicochemical properties of the constituent ions.

The similarity in the conduction behavior of the two ternary

systems is based on the structural similarity of the ions in the base

compositions. The results of the investigation promise new

formulations for glasses, glazes, and ceramic coatings to meet

specific, specialized requirements.

Thermochemistry of Inorganic Materials. Pozzolans are materials

that contain active silica and alumina. They are added to portland

cement to enhance its properties. The calcium hydroxide released

by the hydration of the cement reacts with the active silica or alumina of the pozzolan to alter the properties of the hydrated

cement. As a part of the study of these reactions being carried

out at the Bureau, measurements were made of the heat of reaction

between calcium hydroxide and silica gel. Differential thermal

analyses up to 1,000° C were made of these pastes. The analyses

indicate that calcium hydroxide reacts completely with silica gel at room temperature up to a CaO/Si02 molar ratio of 1.5 and

perhaps even to higher ratios over an extended time. The heat-ofreaction data show complete reaction up to a ratio of 1.0, above

-•'.(»7r;o7— no o 75
which the heat of reaction per mole of Si02 assumed a new and

smaller value. Heat-of-solution data were obtained for several

crystalline hydrated silicates, which will be used in computing their

heats of formation for comparison with the values obtained for the

heat of reaction of calcium hydroxide with silica gel. The crystalline materials present the ultimate possible products of such

reaction, and this comparison permits an estimate of the progress

of the reaction toward completion.

Crystal Structure of the Phosphates. The inorganic solid phosphates are a very large and complicated group of compounds, many

of which are of importance in such diverse fields as detergents and

fertilizers and in the biology of bone and teeth. This group of

compounds has many types of structures similar to the silicates. The first systematic study at NBS of the structure of the trivalent

orthophosphates has been completed. Several of these compounds were found to occur in more than one atomic arrangement

and the range of stability of various forms was also investigated.

Work is nearing completion on the mixed orthophosphates.

Standard X-ray Diffraction Patterns. Standard X-ray diffraction

data is used widely in research and industry as a rapid and precise

method of chemical analysis. The increased usefulness of the file depends on improving the accuracy of the data and increasing the

number of compounds covered. The Bureau has been improving

the file both by replacing conflicting data and by adding data on compounds not previously represented in the file. The program is sponsored by the Joint Committee for Chemical Analysis by X-ray

Diffraction Methods, which is composed of members from the

American Society for Testing Materials and the American Crystallographic Association. Up to the present, 227 NBS standard

patterns have been produced and the data published. These

replace 560 patterns of the original file and add 42 materials not

previously represented.

Phase Studies of the System Lime-Silica-Water. The calcium

silicate hydrates are of great importance to the building materials

industry because they are the principal cementitious agents in

portland cement concrete and in such pressure-cured units as sandlime brick and autoclaved cement blocks. An investigation of

phase equilibria has been completed for the system lime-silica-water

at 180° C, the temperature commonly used in the manufacture of

76
autoclaved' cement products. The study shows that two calcium

silicate hydrates, closely related to the minerals xonotlite and

hillebrandite, are stable at this temperature. The regions of

stability of these compounds, and of quartz and calcium hydroxide, were established. A study of the solubility relationships of some

of the naturally occurring calcium silicate hydrate minerals has

been completed, and an investigation of the lime-silica-water

system at 60° C is under way. -

5 High-Temperature, Ceramic-Mela^Strain Gages. Recently there

has been an increasing need for a completely prefabricated strain

gage that can be used to measure static strains in aircraft and

other structures at temperatures considerably above the 300° F

limit of conventional electrical-resistance strain gages. A program

aimed at developing a ceramic type gage that can be used at much

higher temperatures has been under way during the past year

under the joint sponsorship of the Bureau of Aeronautics and the

Wright Air Development Center. The experimental gage design

showing most promise consists of two alloy filament wires of

0.001-in. diameter, spot welded to thin Inconel strips which in turn are attached to a backing of ceramic-coated asbestos paper.

Such gages, when affixed to an aluminum alloy specimen with an

air-hardening ceramic cement, have been found to measure strains

as high as 1 percent at 800° F. When properly fabricated, the

prototype gage has a low drift rate and a low temperature coeffi- cient. Further work is in progress to improve the reproducibility

of the gage factor and to extend the maximum operating temperature above the present limit of about 800° F. Phase Equilibrium Studies on Portland Cement. A study of the

phase equilibrium in portland cement clinker is being conducted

in cooperation with the Portland Cement Association. During

the past year the ternary system CaO-12Ca0.7Al2 3-2CaO.Fe2C);5 has been investigated. This system constitutes a boundary of

the quaternary system where the iron-bearing solid-solution series

is reported to occur. By the use of differential thermal analysis,

X-ray powder diffraction analysis, and quenching techniques, it has been confirmed that a solid-solution series does exist between

the compound 2CaO.Fe2 3 and a composition in the vicinity of

6Ca0.2Al203.Fe203. The extent of the solid solution range on

77
A knowledge of the composition of the liquid reaction zone of a portland

cement clinker at kiln temperatures was provided for the first time by the

results of phase equilibrium studies at NBS (p. 77). each side of a line 2CaO.Fe203-6Ca0.2Al203.Fe2 3 is also being

investigated.

Previous work has shown that the alkalies Na2 and K2 may

affect the constitution of clinker significantly, even though these

oxides are ordinarily present in cement in amounts of less than

1 percent. This information led to an investigation of phase

equilibria in the senary system K20-Na20-CaO-Al203-Fe2 3-Si02 . This appears to be the first systematic study of phase relations in any six-component refractory oxide system. The investigation of

this complex system was made possible by the use of the hightemperature centrifuge together with the more conventional

methods. From this work, information has been obtained on the

entire course of crystallization of one typical clinker composition

and on part of a second. A knowledge of the composition of the

liquid reaction zone of an actual clinker at kiln temperatures is provided for the first time by these results. Effect of Ceramic Coatings on the Creep of Alloys. Ceramic

coatings are being widely used on components of equipment operating at high temperature to provide protection against such

detrimental effects as oxidation and carbon absorption. Recent

work at NBS, sponsored by the Wright Air Development Center,

78
shows that under certain conditions ceramic coatings can also substantially reduce the creep rate of high-temperature alloys. The

relationship between the chemical composition of the coating and

that of the alloy appears to be an important factor in the effect of the coating on creep behavior. A barium silicate type coating,

containing dispersed particles of cerium oxide for refractoriness,

caused reductions up to 90 percent in the creep rates of 80 Ni-20 Cr

allovs. The results indicate that a real advantage in creep behavior of particular alloys under operating conditions can be

achieved bv the application of suitable ceramic coatings.

As part of the study of possible mechanisms by which a ceramic

coating can affect the creep behavior of metals and alloys, gas

diffusion tests were conducted to compare the diffusion rates of

hvdrogen through ceramic coated nickel and through uncoated

nickel. These tests were conducted at 1,400° F under a pressure

gradient of approximately one atmosphere. The coating applied was NBS No. A-417, which is a barium silicate ceramic coating containing particles of chromic oxide. Although the layeroc of ating was only So as thick as the high-purity nickel, its presence reduced

the diffusion rate of hydrogen to only about 5 percent of its rate through the uncoated nickel.

Reaction of Portland Cement with Carbon Dioxide. Hydrated

portland cement is an alkaline material that reacts with carbon

dioxide in the atmosphere. Experiments have been carried out

at NBS to study the nature of the carbonation process. These

findings show that the rate of carbonation of thoroughly dried

cement can be increased manyfold by increasing the relative

humidity of the atmosphere in which the process occurs. They

further show that there is an optimum moisture content in the

hydrated cement itself at which carbonation occurs most rapidly.

Investigations have also been made of unhydrated cement. The

results indicate that comparatively small percentages of carbon

dioxide can reduce the hydration rate of cement.

Refractory Concrete for Jet Aircraft Aprons. The advent of the

jet plane has necessitated an investigation of materials suitable for pavements as warmup, power check, and maintenance aprons.

These pavements must withstand exposure to high and fluctuating

temperatures. Under the sponsorship of the Navy Bureau of

Yards and Docks, the Bureau has investigated calcined flint clay,
sintered slag, and two lightweight aggregates for high-temperature

resistant concretes. Three types of cement, portland, portlandpozzolan, and high alumina hydraulic, were used with each aggregate. The result of laboratory tests indicate that the concrete

formulated with the calcined flint clay or sintered slag appeared

to be the best for the special requirements. Because of the

comparative weakness of the lightweight aggregates the maximum

flexural strength developed was 600 pounds per square inch.

Numerous tests were performed on the cured and heat-treated

concretes, such as thermal length change, strength in flexure and

compression, resistance to abrasion, elastic properties, shrinkage,

and weight loss. Properties of Glass Fibers. The growing need for lightweight,

high strength structural materials in aircraft and high speed military missiles has increased interest in the use of glass fibers as a reinforcing material. The Navy Bureau of Ordnance has been

supporting a basic investigation into the factors which affect the

physical and chemical properties of glass in the fibrous form.

From previous studies it was learned that some barium-calciumaluminate glasses had Young's moduli of elasticity considerably

higher than commercial types of glass. A study is being made of

the effect of various oxide additions on the Young's modulus,

deformation temperature and fiber forming ability of calcium

aluminate glasses and on the tensile strength and Young's modulus

of fibers of these glasses. The effect of heat treatment on the

physical properties of the fibers is also being studied. The quenching that occurs during fiber formation causes a reduction of the

elastic moduli of the glass by as much as 20 percent. However

annealing of the fibers has regained as much as 98 percent of this

loss. Commercially available fibers have a Young's modulus of

about 10.5 million pounds per square inch compared with a value

of 30 million for steel. The Bureau has produced fibers having

an unannealed value of 15.8 million psi which can be increased

to 18.5 by annealing.

Special Optical Glasses. Glasses with special optical and physical

properties are needed to meet the requirements of new fire control

and other optical instruments for the Armed Services. Research on the development of glasses to meet these needs is being sponsored

by the Navy Bureau of Ordnance. During the year 7,500 pounds

80
of optical glass in the form of molded blanks were delivered to defense agencies

The most promising compositions developed to date at NBS are based on the ternary BaO-Ti02-Si02 system. Five stable compositions have been developed which can be made in practical

amounts and have refractive indices from 1.83 to 1.93, values

which are well above most commercial glasses. These glasses

have good t^ansmittances in the near infrared, deformation temperatures above 800° C, and excellent chemical durability over

the pYL range from 2 to 12. A stable glass composition has also

been developed which has good flame-working characteristics and

a deformation temperature above 700° C.

2.10. Building Technology

Over the past several years the Building Technology Division

has conducted a critical examination of present building practices

and a search for new practices based on sound engineering principles. The major aim is to increase economy of construction and

maintenance. Before full advantage can be taken of the kind of

engineering approach that has guided the rapid technological

development of other industries, the building profession must be

supplied with adequate standards of measurement, new testing

procedures, fundamental engineering data, and performance

standards. Few industrial organizations have the facilities to obtain the needed fundamental engineering data. The building

profession, therefore, depends on the National Bureau of Standards

for basic research in the fields of building materials, structures, and

equipment (excluding forest products which are studied by the

Department of Agriculture Forest Products Laboratory).

The Bureau's fields of interest include structural engineering,

building codes, safety engineering, fire protection, heating, re- frigeration, and air conditioning, as well as building materials,

such as flooring, roofing, and wall finishes. Typical studies completed during 1955, or presently under way, concern durability of

masonry materials, shrinkage stresses of masonry, control of

cracking in reinforced concrete, structural and fire resistance

properties of precast thin-shell concrete structures, fire endurance

tests on building structures, fire detection in aircraft engines, air

filters for helicopter engines, insulation of underground pipes, heat

insulation and heat conductivity, flooring and roofing materials,

I
Typical crack pattern at failure of a loaded reinforced concrete beam. Many

such tests were performed in a study of the cracking of reinforced concrete. and development of portable and mobile military refrigerating

apparatus. The Bureau continued to render assistance to Federal,

State, and municipal bodies on the development of improved

building codes and safety standards.

Instrumentation and Measurement. The Bureau laboratories

have found increasing application for the NBS internal strain gage

developed in 1951. This gage can be cast into concrete or mortar

for determination of length changes due to drying shrinkage,

thermal expansion, and freezing and thawing. Its use externally

for measurement of dimensional changes in stone with wetting and

drying is also a new application recently discovered.

Control of Cracking in Reinforced Concrete. Formation of tensile

cracks in nonprestressed reinforced concrete cannot be avoided,

but the width of cracks can be reduced by increasing the strength

of bond between concrete and the steel reinforcement. In order to provide reinforcing bars having higher bond strength, the steel industry during the past 10 years developed improved deformed

reinforcing bars. As these bars became commercially available,

it became desirable to secure data with beam specimens reinforced

with the new types of bars in order to provide a basis for improved

design practices with respect to control of cracks. Accordingly,

the Research Fellowship of the American Iron and Steel Institute

at NBS, in collaboration with the Bureau staff, conducted a sys- tematic study of the effect of various factors on the distribution

82
Equipment for evaluating flame-spread properties of flammable materials

(p. 83). This equipment makes possible a simple but realistic test method for use by both private manufacturing and commercial testing laboratories. and width of cracks. The studies have shown that the average

width of cracks is proportional to the ratio of diameter of the

bar to the percentage of reinforcement and to the increase of steel stress beyond that causing initial cracking. The average spacing

of cracks decreased rapidly with an increase in steel stress beyond

that causing the first crack, and at a stress of about 30,000 pounds

per square inch the average spacing approached a constant value.

An equation representing the relationship between the average

width of cracks and the several factors which influence their formation was formulated and made available to the engineering profession by publication.

Flame Spread Test Method. When fire breaks out in a building

the rate of its growth is largely dependent on the contents of the

building and the character of the interior finish. Both in this

country and abroad a large amount of time and effort has been

expended on development of methods for evaluating the flame

spread properties of such interior finish materials. The Bureau

has recently completed work that promises a simple but realistic test method suitable for use by both private manufacturing and

commercial testing laboratories.

83
The method consists of equipment for holding a small specimen

of the material to be tested in front of a refractory panel radiating

in a manner very similar to that of a blackbody at 700° C. The

specimen is positioned in such a manner that ignition occurs near the

top of the specimen and the flame front progresses downward. The

rate of propagation of the flame front and the heat release rate of

the material determine a flame spread index. This index appears

to correlate well with burnout tests performed in England on model

rooms as well as with results of tests performed on similar materials by means of much larger and more complicated test equipment. It is believed that this new method of evaluating the

flame spread properties of materials can be used by industry as a method of studying and controlling the flame spread properties

of manufactured materials for interior finish application.

Aircraft Fire Detection. The problem of locating and reporting

the presence of fire in aircraft engine spaces is a vital one. It is complicated by the fact that exhaust fittings of engines frequently

operate at very high temperatures and leakage of combustion gases

is not uncommon. The Bureau has recently completed a study,

for the Air Force, of the characteristics of flames that might be

used in the detection of accidental fires. Although more than 30

different methods were considered for detection of fires, major

emphasis was placed on study of their radiating characteristics.

The study indicated that a reliable fire detection device could be

based on a radiation detector that would function only on receipt

of both a low-frequency modulation and a rapid increase of the

energy received.

Water Usage for Drinking Water Coolers. A field study of water

demand rates from electric drinking water coolers was made to provide a basis for judging the validity of the capacity and peak

draw requirements incorporated in the Federal specification for water bubblers. Sixteen stations were selected for study in office buildings, mess halls, classrooms, military barracks, a garage, and

a bus terminal. Data were taken by photographic methods to determine the number of individual drinks taken and the duration

of the drinking period at each station for periods ranging from 7

to 22 days.

The study showed that an hourly water usage in the range

from 0.05 to 0.075 gal/hr per person can be expected in hot weather

84
Effects of moisture and temperature on insulated concrete roof decks were

studied (p. 85). Fifteen roof-deck specimens with eight different insulations were exposed to simulated climatic temperature conditions.

for persons engaged in relatively light work. The average duration

of a drink from these bubbler coolers was 6 sec and the average

water usage was 0.055 gal per drink. The average hourly water

use did not reach the nominal 10 gal/hr capacity of the coolers at any of the 16 stations. The study showed that the ratio of the

water usage rate for a 15-min period to the average hourly rate was higher in most of these installations than that now required

in Federal specifications.

Effect of Moisture on Roof Deck Insulation. Concrete roof decks

of buildings are commonly insulated with thermal insulation laid

between the deck and the built-up roofing. Since the roofing is practically impervious to water or water vapor, moisture sealed

into the insulation when it is covered, or condensation occurring

during service, can seriously affect both the effectiveness and durability of the insulation or cause blistering of the roofing. A study

of such effects is in progress for the Office of the Chief of Engineers,

involving exposure of 15 roof deck specimens with 8 different

insulations to simulated climatic temperature conditions. These

include seasonal temperatures representing summer, moderate

winter, and severe winter conditions, each for a term of a month

85
or two of repeated daily cycles of temperature change simulating

daily solar heating and night cooling. Results to date indicate

a marked effect of moisture on insulating value, the effect being

significantly different for different seasonal levels of temperature.

Information is also being obtained as to the timelag of under-roof

temperatures resulting from daily solar heating, with different types

of roof insulations.

Performance of Air Cleaners. At the request of the Public

Buildings Service of the General Services Administration, the

Bureau has been investigating the air cleaning efficiency and

dust-holding capacity of several types of air cleaners and filters. The 'information is needed to revise the current Government

specifications for such equipment, and to include requirements

for new types of air cleaners. Tests were performed on 5 electrostatic air cleaners, 2 automatic oil-type air filters, and 3 throwaway

or cleanable type air filters. The data include measurements of

the dust-arresting efficiency by the Dust Spot method with at- mospheric air and with Cottrell precipitate dispersed in atmospheric

air.A Study of a Ceiling Panel Heating System. As a part of the

nvestigation of heating systems for small houses being conducted

for the Housing and Home Finance Agency, the performance

characteristics of a ceiling panel heating system were studied with

a full scale installation in the Test Bungalow. The entire ceiling area of the five rooms of the bungalow was equipped with heating

coils of %-inch copper tubing spaced on 4-inch centers and divided

into 10 circuits. An electiically-heated boiler permitted accurate

measurement of the total heat input to the ceiling panel, and 20

heat flow meters above the panel provided measurements of the

reverse heat loss to the attic. Thus the downward heat emission

of the panel could be determined with considerable accuracy and

could be correlated with the average ceiling temperature as measured by an extensive thermocouple system. The heat transfer

rates observed were only about two-thirds of the values published

in currently-used handbooks which are based on separate computations of radiation and convection heat transfer. The heat loss of the house was not excessive with this heating system, and was

comparable with that observed for a baseboard convector system

in the same structure.

86
Asphalt Roofing. Progress has been made in the study of the

mechanism of weathering of asphalt. A chromatographic method

has been developed for the separation of asphalt into four distinct

groups of components. This method serves as a basis for current

studies of chemical and physical changes that occur in asphalt

during the weathering process. Work was initiated on about 20

asphalts to determine the chemical composition of the asphalts

and their components, before and after weathering.

Several techniques have been developed to collect and identify

the degradation products of asphalt. Work is under way to separate the complex mixtures of polyfunctional compounds into

individual species by chromatographic and distillation methods.

Roof Maintenance Manual. Very little has been published on

the maintenance and repair of roofs, a subject of great importance

to the armed services. At the request of the Office of the Army

Chief of Engineers, and the Navy Bureau of Yards and Docks,

the Bureau made a study of roofing conditions in representative

Army and Navy field stations throughout the United States and

in Hawaii and Guam. The Bureau analyzed replies to questionnaires concerning roofing practices and problems that were sent to Army and Navy area headquarters throughout the world. With

this information and on the basis of previous experience, a comprehensive roof maintenance manual was prepared by Bureau

staff members. Use of this manual by field engineers should result

in large savings to the Government.

2.11. Applied Mathematics

The Bureau has for a number of years maintained a central

applied mathematics facility which conducts basic and applied

research and renders advisory services in various mathematical

fields. Such services are available both to the Bureau's technical

staff and to other Government agencies. Equipped with modern

computing aids including high-speed digital and analog computers,

the applied mathematics facility has played a significant supporting

role to the Bureau's research and development program. During

the past year, research emphasis was placed on statistical and

numerical analysis, and mathematical physics. Special assistance was rendered to the Bureau's staff and other Government groups

87
in these areas and in digital computation. In addition to consulting services in applied mathematics, including mathematical

statistics, special attention was given to problem formulation and

analysis to determine applicability of numerical methods to solution of problems on automatic and nonautomatic computing

machines. The work covered a wide range of investigations and

applications in the physical and engineering sciences.

The Bureau's applied mathematics program has been strengthened by the active interest and support of other Government

agencies. Especially significant is the support of fundamental

and applied research in numerical analysis and mathematical

physics by the Office of Naval Research and the USAF Office of

Scientific Research.

Numerical Analysis. Linear systems were extensively investigated and methods for determining characteristic numbers and

functions of matrices were devised and used on the computer

SEAC. Such work is essential in certain theoretical analysis,

analysis of vibration for example, and in the solution of other

important problems arising both within and outside the Bureau.

In this connection, special attention was given to the preparation

of efficient general-purpose solutions, of wide applicability, yet

suitable for solving current problems. For example, a general

theorem was proved which established the positiveness of characteristic members of matrices arising in the theory of dielectic

relaxation. Theorems were proved on the bounds of the characteristic numbers of matrices. The latter gave important results

for use in analyzing critical vibration frequencies as well as for developing effective methods of actually computing the characteristic numbers themselves

The stability of nonlinear differential equation systems was

investigated. The Liapunov theory was applied and the various

definitions of asymptotic stability were studied with a view toward

unifying the great number of presently available results. A war games model, represented by a system of six nonlinear

differential equations was analyzed theoretically. A necessary and

sufficient condition was proved for the victory of a party over its opponent. Victory was described by the magnitudes of the

offensive forces' ultimate values and the production rates of the

antagonists.

88
SEAC—The National Bureau of Standards Electronic Automatic Computer

in its new quarters.

Important numerical experimentation was conducted during the

year. For example, complex orthonormalizing SEAC codes were

developed and applied to numerical experiments in conformal

mapping, potential theory, and the solution of elliptic type boundary value problems. Also, various methods of generating random

numbers were tested to determine their suitability for the Monte

Carlo evaluation of highly multiple integrals of the type frequently

occurring in statistical mechanics. Experimental computations

were performed using this sampling method of evaluating such

integrals.

The compilation of a complete file of programs for matrix computation on SEAC was begun. Numerous useful computational

codes and devices were developed. SEAC instruction codes were worked out for summing slowly convergent series and for Gaussian

quadrature rules of high order. The latter were developed to meet

the specific need for numerically evaluating integrals where integration rules of great accuracy are essential.

Digital Computation. During the year the computation program continued at a high level of activity. The Bureau's highspeed digital computer SEAC was in use three shifts daily, except

for the 2-month period needed to move it to its new permanent

location. Computing services for supporting the Bureau's research

and development program were significantly advanced during the

year. As part of the computation program, the following mathematical tables were edited and published: Collected Short Tables

of the Computation Laboratory, Tables of Secant and Cosecant,

Tables of the Complex Gamma Functions, Tables of the Sine and

Cosine Integrals. In addition, NBS mathematicians and data89
processing experts collaborated in training and providing programers for data processing problems.

The Bureau staff has shown considerable interest in having

problems programed for solution on SEAC. This has led to significant time saving services. The following list illustrates the

extent of service rendered to other Bureau programs: preparation

of high-temperature thermodynamic tables; calculation of virial integrals, involving Morse potential functions; computation of

vibration modes and frequencies; Lovibond network for CIE

source A; velocity of light calculations; molecular vibrations;

compressibility factors of dry air; frequency correlation in a microphone problem; characteristics of conducting resistors; transient heat flow problems; Wiechert distribution functions; electromagnetic radiation from lightning; parameters of the dispersion

equation for optical glass; thermometer calibrations; stresses in a wall foundation; temperature distribution in solid wings heated

aerodynamically; distribution of light output from neutron spectrometers; aeronomic tidal winds of thermal origin; and optical

ray tracing.

A wide variety of problems were solved and cooperative services

rendered to other agencies. Typical of these were the following:

procurement contract award by linear programing, New York

Quartermaster Procurement Agency; atmospheric waves, Weather

Bureau; turbulent atmospheric contamination, Applied Physics

Laboratory, elastic cross section for neutron scattering, Naval

Research Laboratory; integrals arising in supersonic flutter, National Advisory Committee for Aeronautics; dosage integral,

Weather Bureau; ball-bearing fatigue data, American Standards

Association; Loran computation, U. S. Naval Hydrographic Office;

Maryland interindustry study, Department of the Air Force;

heat convection analysis, University of Minnesota (AEC); liquid

vapor transition problem, Naval Medical Research Institute;

neutron transport problem, complete degradation in the neutron,

and alpha analysis problem, Atomic Energy Commission; integral

of a product of bessel functions, Office of Naval Research; reflection

onto a vertical surface on a lambert plane, Armed Forces Special

Weapons Group; reactor design, Westinghouse Atomic Power

Division (AEC); Missouri River flood problem, Army Corps of

Engineers; and data processing problem, Navy Bureau of Supplies

and Accounts, U. S. Navy.

90
Statistical Engineering. The statistical engineering program is designed to advise both the Bureau staff and other Government

agencies on the application of modern probability and statistical

methods to the physical sciences. To maintain and increase the

effectiveness of this program, basic research it probability theory

and mathematical statistics was conducted during the year. The

Bureau rendered extensive statistical advisory services during

the year, and prepared manuals and bibliographies on selected

phases of statistical methodology.

During the past year, this research, geared to fit the particular

needs of NBS laboratories, fell into two categories: (1) planning

and analyzing experiments (design of experiments) ; and (2) extreme

value methods.

Under the first category, research continued on the arrangements

known as partially balanced incomplete block designs. These

designs have recently been introduced in several Bureau laboratories. By applying the theory developed, the research worker

engaged in constructing this design may concentrate his efforts on

those arrangements most likely to yield satisfactory results. For

this purpose a catalog using selected subsets of all possible combinations was recently prepared, under the sponsorship of the

Army Chemical Corps.

The second main research effort concerned the further development of the theory of extreme values. There are many applications

in which the primary interest is not average values but the largest or smallest extreme—in the preparation of building codes, for example, where maximum wind loads are of concern. The Bureau

has developed new and more precise methods for treating extreme

value data.

As a consultant and advisory service, experimental designs were worked out for use in intercomparing four national radium standards. Instead of establishing one standard as correct by definition,

the consensus of all four of the national standards was used. The

consensus value arose naturally in the statistical analysis asso- ciated with the intercomparison. This approach possibly may be

generally useful in future international standardization. If each

nation's standards are referred to the consensus value they can

be intercompared and the value relative to the consensus re- determined, even if one or more of the national standards is absent.
Further, no one nation is charged with the responsibility of maintaining the ultimate standard as is the case with the meter bar.

The dependence of fatigue life of ball bearings on bearing load was studied at the request of the American Standards Association.

The primary aim of the study was to determine the best value for a dominant parameter in the life formula used by the bearing

industry, giving the number of revolutions needed for a specified

percentage of ball bearings to suffer fatigue failure. The need for the study originated from lack of agreement on the parameter

within the industry. Because bearings have extremely long lives,

many tests are terminated before all bearings in a test group fail. As a result, many test groups contain intact bearings. Therefore,

statistical procedures were devised which properly allow for such

survivors. This work has also given several useful statistical

byproducts.

The extent of statistical services rendered during the year was

comparable to the number of testing activities at the Bureau.

The design of experiments by the Bureau laboratories has been

facilitated by the Bureau's program in statistical engineering.

The objective has been to obtain sufficient data for fruitful statistical inference with a minimum of laboratory testing. In addition

statistical analysis was employed in the formulation of a number

of the problems solved by high-speed digital computation.

Mathematical Physics. Bureau work in this field has been

concentrated mainly in theoretical aerodynamics, hydrodynamics,

elastic equilibrium, elastic vibrations, and electromagnetic and

acoustic diffraction theory. One Bureau problem, for example,

concerned the effects of dissipation upon the disturbance rare- faction waves set up in an air brake line, or, more generally, in any

type of pneumatic controlled circuit. This question was first studied using the simplified assumptions that frictional effects merely produce retardations of the flow and that entropy changes

can be disregarded. The model was then made more realistic and

extended to include entropy and energy changes in the gas. This

required using the full nonlinear system of differential equations

consisting of momentum, continuity, and energy equations. Exact

analytic solutions were obtained for both the constant entropy

model and the more realistic one.

92
The work on unsteady gas flow was paralleled by research on

the transonic-supersonic region in steady gas flow from nozzles.

Wind tunnel nozzles which produce supersonic flow can be designed

by known methods, if the nozzle boundaries are restricted to small

curvature. Small curvature nozzles are long and expensive. For

economy, short nozzles with large curvatures would be desirable.

A method of nozzle performance analysis was developed which

uses the Mach line originating from the throat of the nozzle (the

S-line) as the carrier of the necessary initial data. Using this

technique short nozzles can be designed in which the pressure

gradient decrease is as uniform as possible. In the field of elasticity, the vibration problem for plates was

attacked from a new standpoint. Previous mathematical attempts

on this problem have been confined to rough engineering methods

using "influence coefficients" and simple beam theory. Successful

solution demands a direct attack using elastic plate theory. The

effect upon accuracy of the numerical solution was studied when

finite difference expressions are improved only for the boundary

derivatives, without refining the mesh width in the interior domain.

For the square clamped plate, this technique gave significant improvement in the determination of the lowest mode. At the

request of the Air Force the vibration and flutter problem for triangular wings of jet delta-wing craft was investigated. This

task required combining knowledge of elastic plate theory with

electronic computer experience. Successful formulation covering

all delta-wing shapes required solving an unsymmetric matrix

eigenvalue problem. Final results await completion of a new

SEAC code needed to handle the large matrices involved. However, preliminary results on smaller, sample matrices were obtained

that promise great utility for the method.

Other mathematical physics investigations concerned displacement and stress characteristics of corrugated elastic diaphragms,

the basic element in altimeters and gas pressure instruments, and

the solution for the diffraction field (two or three dimensional)

from a dipole radiation in the neighborhood of a wedge of arbitrary

angle. The result of the latter study applies both to an acoustic wave and to an electromagnetic wave, if in the second case the

dipole axis is parallel to the edge of the wedge.

93
2.12. Data Processing Systems

The Bureau's data processing systems program encompasses

research, development, systems design and analysis, and technical

advisory services in both digital and analog computer technology.

This program, developed during the postwar years, originally began

with requests from several Government agencies for assistance in evaluating the potential application of automatic electronic digital

computers to their problems and in procuring suitable installations.

The evaluation studies and procurement eventually led to the

Bureau's program of research and development of improved computer components and circuitry and subsequently to the design

and construction of SEAC. This machine was the first superspeed electronic digital computer to go into productive operation

(June 1950). Since then, SEAC has established an impressive

record of solutions for both scientific and management problems

for the Bureau and other Government agencies.

This technical effort and the increasing demand from Government agencies for advice on applying these powerful tools led to an expanded workload in research and development of new and

improved components, circuitry, and auxiliary devices, in the

development and design of more powerful logical systems, and in the analysis and application of data processing systems for the

solution of business and management problems. An outstanding

achievement of this program was the design and construction of

the first mobile high-speed general purpose computer, DYSEAC,

designed as an experimental nucleus for a complex data-processing

network for the Department of Defense.

Recognizing the importance and potentialities of this expanding

technology, the Bureau this year established a separate division

which combines the functions of the digital computer laboratory

with those of an analog systems laboratory. This unit provides

probably the most comprehensive and readily available Government source of information in the new and rapidly growing field of high-speed automatic data-processors. The broad background

and experience of NBS laboratories has resulted in an increased

number of requests from many Government agencies who seek

the Bureau's technical advisory services on high-speed digital

techniques in new areas of potential application such as massive

paperwork operations, control systems, and simulation, as well

94
Packaged circuitry of this type (actual size shown) is expected to simplify

construction and maintenance of electronic computers (p. 96).

as in the solution of specific technical problems. The possibility

of combining digital and analog techniques in the development of

simulators and control systems is an area which is now being

explored.

SEAC. The experimental modification, operation, and maintenance of SEAC has been a continuing responsibility. During

the past year, the complete installation was moved to more permanent quarters. The move included an improved physical layout

of the machine, both in space and chassis arrangement. Regulated power supplies for low-voltage distribution were installed in advance, and new circuitry was incorporated for a 3 address-4

address switch at the operator's console. Other minor modifications were made to improve reliability, facilitate maintenance and

increase safety of operations, as well as to provide for additions of

auxiliaries and the connection of display equipment. The loss of

only 2 months of computation time indicated the effectiveness of

the preliminary planning and preparations. The machine has

returned to its through-shift schedule.

Analog Computers. To provide analog computation facilities to meet the technical needs of the Bureau, a modest analog installation was purchased and put in service. A work program in the

development and design of simulators and control systems which

may utilize analog and/or digital techniques has also been initiated.

One program involves the design of a jet-engine simulator for Navy Bureau of Aeronautics, in cooperation with Aircraft Industries Association. This device will facilitate the development of

engine controls simulation concurrent with the development of

05
new jet engines. Another task is the development of a special

fallout computer for the Weather Bureau.

Development of New Computers. At the request of the NBS

technical advisory committee, established by the Policy Committee

for Mathematics, a preliminary systems study was initiated and

tentative system plans devised for a powerful computer, which

will be 100 times as fast as SEAC for solving a large class of scientific problems. Preliminary specifications for this machine were

presented to the advisory committee.

Studies were also completed on the feasibility of applying

digital computer components and techniques to a large-scale naval

tactical trainer. A tentative over-all computing and control

system was formulated which will be capable of meeting those

computational and engineering requirements by means of presently

available digital computer techniques.

Computer Circuitry Packaging. Efforts have continued to improve the modular type of circuitry packaging. Several prototype packages were designed and constructed for the Air Force

Cambridge Research Center, based on the DYSEAC computer

package but having radically decreased power consumption and

increased logical capabilities. This should make feasible the

building of larger and more powerful computing machines without

the necessity of extremely large power supplies and air conditioning

equipment.

Diode Amplifier. Research on the application of semiconducting

diodes has led to the development of a new class of amplifiers that

utilizes the reverse transient phenomenon of these two-element

rectifying devices. The diode amplifier—using no vacuum tubes

and achieving power gains up to 10 per stage—promises important

application in the future design of high-speed electronic digital

computers. For example, it may be used as a pulse repeater stage,

in varied types of flip-flop circuits, or as a wide-band, flat-response

amplifier. Because suitable diodes are now in regular production,

commercial applications appear practical at the present time.

Future improvement in the manufacture of diodes may make the

principle useful for amplification at even microwave frequencies.

Cold Cathode Gas Diodes. With the increasing use of electronic

digital computers, complex problems have been presented which

require for their solutions high-speed memories so large that

96
present-day costs make them economically impractical. The

cold-cathode gas diode—such as the simple neon glow lamp

offers possibilities for low-cost high-speed memories, once the

inherent disadvantages of the tubes are overcome. The Bureau

undertook a study of these visual-indicating tubes for memory and

indicator circuits. This study has resulted in design of a number

of circuits that provide an approach to reducing the cost of digital

computer memories from the present dollar per bit (binary digit)

to about 10 cents. It has also been found possible to utilize such

diodes in indicating devices since in most of the circuits considered

the lamp will be luminous in only one of the two stored states. An inexpensive method for equalizing and stabilizing the voltage

characteristics of cold-cathode gas diodes—such as neon indicator

lamps—has been developed. The tube characteristics are improved by a process of aging in which pulsed voltages are applied

simultaneously to a large number of tubes. Trials of the processed

tubes in actual operating circuits show that these aged diodes are reasonably stable. The method promises to provide an inexpensive, easily available component for many practical applications in automatic electronic computer circuitry. The gas diode program was sponsored by the Air Force Cambridge Research Center.

Other Diode Studies. Semiconductor devices promising improved performance in digital data processing machines were

tested and evaluated and circuitry using gas diodes and diode

amplifier techniques, and magnetic devices was developed for the

Air Force Cambridge Research Center. A novel gas-diode indi- cator memory circuit was developed to be used in the design and

construction of a data correlator and classifier for the Naval Research Laboratory. The solution of the indicator memory problem

has broad applications in those fields where data must be presented

for visual analysis.

Magnetic Core Investigations. Magnetic devices for amplifying

and switching pulses have been studied in the hope of replacing vacuum tubes in SEAC type computer circuitry. Two circuit

configurations were tried out in the form of simple shift registers.

Magnetic core memories are also being studied, with particular

emphasis on word organization.

Rotating Reading Head. A reading head that makes possible the

close examination of a short section of magnetic tape or wire is now

97
Rotating reading head for close, repetitive examination of a short section of magnetic tape or wire (p. 97). being used at the Bureau to locate and investigate faults in magnetic recording media. This instrument, constructed under the

sponsorship of the Office of the Air Comptroller, makes use of a reading head mounted on a rapidly rotating drum so that the head

is in contact with the tape for a part of each revolution. Since the

tape is held stationary, the head reads exactly the same set of

signals once each revolution, and the playback can be displayed

continuously on an oscilloscope and observed as long as desired.

High-Density Magnetic Tape Recording. A method for closely

packing digital pulses on magnetic tape has also been developed

for the Office of the Air Comptroller. This method promises

future useful application in the field of electronic computers.

Such high-density storage can greatly reduce problem solution

time by providing more rapid access to information recorded on

external magnetic tape units. In a series of experiments at the

Bureau, both continuous-current and pulse techniques were investigated to achieve densities in the range of 500 to 700 pulses/in.

98
Recording and reading circuitry was developed to provide largeamplitude playback signals with error-free differentiation between

binary ones and zeroes.

2.13. Cryogenic Engineering

The NBS cryogenic engineering program has as its objectives to provide engineering data on the properties of materials at very low

temperatures and to investigate cryogenic (low-temperature)

processes and devices that will be of benefit to industry and the

national defense. There are today many large-scale applications

of cryogenic processes which involve the liquefied gases: oxygen,

nitrogen, hydrogen, and helium. For example, all the nation's

helium is concentrated by low-temperature processes. All the

oxygen for welding and metals refining is produced from the lowtemperature distillation of air. In the realm of national defense,

many of the new rockets use cryogenic fluids as fuels and oxidants.

It has long been recognized that liquid hydrogen is the most

powerful of all chemical fuels on a weight basis. As a result of

these developments, a variety of complex engineering problems

have arisen in this field. The Cryogenic Engineering Laboratory was established for the

initial task of assisting the Atomic Energy Commission with a project requiring large-scale low-temperature technology. Recently the requirements of the Atomic Energy Commission have

diminished, and it has been possible to undertake a broader

program of research in the field of cryogenic engineering. During

1955 typical projects dealt with flow of liquefied gases, insulation

for liquefied gas containers, separation of hydrogen isotopes by

low-temperature distillation, transporting helium as a liquid

rather than as a gas, and storage of liquid parahydrogen.

Cryogenic Equipment. Basic studies were conducted on the

flow of liquefied gases to enable more efficient and economical

transfer and to predict the performance of transfer systems.

Pumps for transfer of liquefied gases were also investigated.

Initial emphasis has been on the problems of cavitation, shaft

seals, bearings, and insulation, using commercially available

equipment.

Further improvements were made on a vessel for efficient storage

of liquid parahydrogen. Loss rates of 0.25 percent per day were

99
Liquefier building of the Cryogenic Engineering Laboratory, Boulder,

Colorado, where low- temperature liquefied gases for research are produced

in quantity.

attained by application of improved cryogenic techniques. For

instance, improved surface preparation made possible a reduction

in radiation heat transfer.

Certain applications require that liquefied gas containers have

insulation effectiveness for short periods only. An investigation was started on insulations suitable for this application. Basic

consideration is being given to thermal conductivity, ability to withstand thermal shock, ease of operation, and weight-versusvolume relationship.

During the past year the Bureau has been cooperating with the

University of California Radiation Laboratory to develop a large

(350-liter) liquid-hydrogen bubble chamber. Research in highenergy physics has recently led to development of the bubble

chamber as an elementary particle detection device. The use of liquid hydrogen as the bubble-chamber liquid is very desirable.

Successful development of this bubble chamber will provide

physicists with a powerful new tool, but many problems must first be solved. For instance, large glass windows at low temperatures

are necessary for proper observation of the bubble-chamber liquid,

and methods of rapidly superheating the liquid hydrogen are required.

Cryogenic Processes. In 1954 research was begun on the separation of hydrogen isotopes by low-temperature distillation of liquid

hydrogen. With the advent of electrical energy from nuclear

power, a considerably increased demand for heavy water can be

expected, and its cost will be a significant factor. Previous

studies have indicated that low-temperature distillation will yield

100
deuterium gas at a potentially low price. Experimental work is aimed toward the design of large distillation columns for separating

hydrogen isotopes. Initial results show that the separation is quite feasible. The economy of the process will be evaluated by

operating a small pilot plant. In connection with the distillation studies, experiments have been

carried out on heat transfer between a condensing vapor and a boiling liquid. These experiments have yielded results which may

have a bearing on other fields—for example, industrial production

of oxygen.

A study is being made of the technical and economic feasibility

of transporting helium as a liquid rather than as a gas. As a

result of accumulated knowledge on Dewar design, excellent

storage containers for liquefied gases can now be built, and this

makes it possible to store helium in the liquid form for weeks without any loss. A shipping container for a given amount of liquid

helium will weigh only about one-sixth as much as the highpressure steel cylinders required to ship the same amount of gaseous

helium. The saving in weight will make emergency air transport

quite feasible.

Low-Temperature Properties of Materials. Commercial machines

for tensile, fatigue, impact, and hardness testing have been adapted

for low-temperature measurements in order to investigate thoroughly the mechanical properties of structural metals, alloys,

glasses, and plastics used in cryogenic equipment. Stress-strain

data in tension on numerous uranium samples were obtained for Los Alamos Scientific Laboratory, and a beginning has been made

in testing aluminum alloys, copper, copper alloys, and glass.

The bonding and calibration of commercial resistance strain gages

at very low temperatures was studied thoroughly. A comprehensive bibloigraphy of low-temperature mechanical properties is being assembled.

A dual apparatus for measuring thermal conductivities of solids

down to 3° K was put into operation. The discovery that a free- machining leaded copper has nearly as high conductivity as highpurity commercial copper will be of value to designers of cryogenic

apparatus. An NBS Circular was published giving the results of

a comprehensive study of the published data on thermal conductivities of metals and alloys at low temperatures.

101
The heat flow across laminated solids was examined experimentally down to 20° K. In the case of stainless steel, a poorly

conducting alloy, it was found possible, through lamination, to reduce the heat conduction by as much as two orders of magnitude

while retaining essentially the full compressive strength of the

parent material.

The reflectivities of a large number of good- reflecting metal

surfaces were measured at 76° K for thermal radiation having an energy-wavelength distribution characteristic of room temperature.

The results of this work now provide a valuable guide to the design

of evacuated reflective (i. e., Dewar-type) thermal insulation. In

order to predict the long-term performance of such insulation, the

slow fouling of reflective surfaces in continuously pumped high vacua was studied.

The transfer of heat across a variety of evacuated powders was

measured down to 20° K as a function of interstitial gas pressure. The apparent conductivities of such strikingly diverse materials as

silica aerogel, perlite, diatomaceous earth, plastic microbubbles,

and flake aluminum were found to differ only a few-fold from each

other. Experiments with silica aerogel in which the higher of the

two boundary temperatures was varied show the interesting result

that radiation is the predominant mechanism of heat transfer.

The recent commercial development of custom or "in-place"

foaming of plastics has created interest in this process as a possible means of insulating tanks for cryogenic liquids. During the year, Wright Air Development Center and Redstone Arsenal sponsored

tests of the thermal and mechanical performance of such insulations.

The apparent thermal conducth ities of plastic foams were found

to be considerably higher than for either evacuated powders or reflective-high-vacuum insulation, and their resistance to thermal

contraction stresses is poor. However, the mechanical simplicity

possible with such insulation makes it attractive for some applications.

Liquefaction of Gases. Although requirements for the year were

considerably less than for previous years, about 14,000 liters of

liquid hydrogen and 285,000 liters of liquid nitrogen were produced.

These materials are used extensively at NBS for low-temperature

research and engineering development; they are also distributed to other government agencies. In the operation of the plant, emphasis

102
was placed on economy and maintenance of potential for large-scale

liquefaction on reasonably sho^t notice if the need should arise. Several improvements and modifications were made in the plant.

Among these was a supercharging system which increased the

capacity approximately 20 percent. This gave the equivalent of

sea-level operation at Boulder, Colorado (5,400 feet elevation).

Another improvement was a liquid transfer arid storage station for

safe, economical handling of liquid hydrogen. An interesting modification to the plant was conversion of one of the liquefiers to produce liquid helium instead of hydrogen. A test run of a little over

1 hour gave a yield of 120 liters per hour with the plant operating

at two-thirds capacity. Should the demand warrant, the yield of

liquid helium could be made to approach 200 liters per hour.

2.14. Radio Propagation Physics

As a part of its program in radio propagation physics the Bureau

collects, analyzes, and interprets basic data on radio wave propagation over long distances through the earth's outer atmosphere.

It also centralizes and coordinates such information on a national

and international basis. Because the ionosphere plays a determining role in the long-distance propagation of radio waves, a major portion of the program is devoted to study of this medium.

Theoretical and experimental studies are carried out to obtain a better understanding of the formation of the ionosphere, the causes and characteristics of ionospheric disturbances, and the interaction

of radio waves with the ionosphere. Because the sun is active in forming and disturbing the ionosphere, studies of the sun as well as of other cosmic sources of radio noise are included. The program

involves direct operation of 8 ionospheric sounding stations; co- operation in the operation of 7 additional stations; and the assembly,

analysis, and distribution of data received from approximately 60

other stations throughout the world. In addition, permanent,

temporary, and mobile field stations are used for special experiments. The stations are also to carry out research experiments in which geographic location is a matter of importance.

Regularly received ionospheric sounding data are combined with

indices of solar activity received from associated solar observatories

and are used in preparing advance predictions of optimum fre103
Radio telescopes installed at Gunbarrel Hill, near Boulder, Colorado, for measuring radio noise reaching the earth from the sun and outer space. Such phenomena affect communication and radio navigation service in the

VHF range. quencies for long-distance communication throughout the world.

These predictions are published each month and apply to a period

3 months after publication.

Besides the gradual changes in ionospheric characteristics, shortterm disturbances associated with magnetic storms at times seri- ously interfere with radio communications. These interferences

are especially common in the important North Atlantic and North

Pacific regions. Two radio warning services are therefore operated

for these regions. By observation of solar activity, disturbance of

the earth's magnetic field, and radio operating reports, the Bureau

is able to issue short-term warnings in anticipation of such disturbances.

Marked progress was made during the year in finding the source

of discrepancies between current propagation theories and observations made on long propagation paths. A new series of observations on low-frequency radio atmospherics was started, studies of ionospheric absorption were broadened to include observations of cos- mic noise during an eclipse, and observations over paths tangent to the auroral zone were begun.

Oblique Incidence Studies. Much higher frequencies are reflected

from the ionosphere at oblique than at normal incidence. However, the maximum reliable frequency for radio communication at 104
oblique incidence is usually inferred from normal incidence measurements. An analysis of communications records has shown that

communication (and therefore reflection) often takes place at fre- quencies several percent higher than current theory would indicate

possible. A series of tests is therefore being made primarily to study this effect but secondarily to study ionospheric reciprocity

and to determine the ongin of backscatter echoes. In this experiment, the prediction techniques are checked for all times of day

and all frequencies over chosen paths by means of vertical incidence

midpoint ionosphere soundings made simultaneously with oblique

incidence soundings over the path. Studies made on a path from

Sterling, Virginia, to Boulder, Colorado, showed a scattered echo

received at frequencies too high to agree with existing theories of

ionospheric reflection. These echoes offer a clue toward resolving

the present inaccuracies.

Low-Frequency Propagation . Research at low frequencies bridges

the two fields of radio propagation and upper atmosphere physics

and is designed to provide new information about the lower ionospheric regions applicable to widely different fields, such as highaltitude rocket flights and ionosphere propagation by means of

VHF forward scatter. During the year, the Bureau made simultaneous observations at several widely separated stations of lowfrequency atmospherics—the radio signals originating from lightning discharges. In this way it was possible to determine simultaneously the attenuations suffered by low-frequency radio waves

throughout a wide frequency band and over long distances.

Ionospheric soundings a 1" low frequencies are limited by low

radiation efficiency from antennas of practicable size. A 3,400-foot

antenna for this purpose is now being constructed across the top of

a Colorado mountain canyon.

Cosmic Noise. Cosmic and solar radio waves reaching the earth

from outer space limit the minimum usable signal levels for FM

broadcasting, television, and communication and radio navigation

services in the very-high-frequency range. However, observations

of the intensity of this cosmic noise provide a sensitive indication

of the absorption undergone by radio waves in passing through the

ionosphere. Thus from data on cosmic and solar noise, certain

characteristics of ionospheric constitution can be inferred. During

the solar eclipse of June 20, 1955, a small expedition was sent to the

105
Philippines to obtain measurements of cosmic noise at 10 megacycles. The experiment was designed to study the effective rates

at which electrons and ions recombine in the lower region of the

ionosphere, where daytime absorption mainly occurs. Arctic Radio Propagation. Although x^rctic ionospheric propagation has been studied intensively, much remains to be learned

about the auroral absorption zone. It is not known, for example,

precisely where the zone exists relative to the visual auroral zone, nor how its location may change with time during magnetic

disturbance. Moreover dependable measurements of radio wave

attenuation over long paths in or through the Arctic are extremely

scarce. Previously a series of observations has been carried out on paths which cross the auroral zone at right angles. Receiving

stations are now being installed at Fairbanks and Anchorage,

Alaska, to observe signals from Beltsville, Maryland, and from

Bismarck, North Dakota. These installations provide paths

essentially tangent to the auroral zone, the paths differing primarily

in their geographic location. The path lengths are very nearly

equal, but the path to Fairbanks crosses the accepted maximum of

the visual auroral zone while the path to Anchorage does not. Thus direct and accurate comparisons can be made of the simultaneous relative attenuation over the two paths.

International Geophysical Year. Planning for participation in the International Geophysical Year was begun. The Radio

Propagation Physics Division will operate two new ionospheric

sounding stations on islands in the Pacific, will be responsible for ionospheric sounding at five stations on the Antarctic Continent

(including one located at the South Pole), and will provide technical

assistance to four South American countries in installing and

operating new sounding stations. The program also calls for controlling the quality of data received from some 24 ionospheric

sounding stations and for review and publication of their data.

An experiment is planned to study propagation in equatorial

regions by ionospheric forward scattering at very high frequencies.

A new model of ionospheric sounder has been designed, and

contracts let for 12 units. Because of the long shipping time

necessary, work is actively under way on the outfitting of the

South Pole station.

106
Control truck used to redetermine the speed of light by a radio-interferometer

method (p. 107). The value of 299795.1 ±3.1 km/sec derived from these meas- urements is in close agreement with another value obtained independently

by the molecular constants method (p. 107). Speed of Light. A radio-interferometer method has been employed to obtain a new determination of the speed of light. This

method makes use of phase-shift measurements on very-highfrequency radio waves to obtain their velocity of propagation.

The value of 299795.1=1=3.1 km/sec derived from the measurements

is in close agreement with another value obtained independently at NBS by a molecular constants method (see page 107).

For the interferometer method, two receiving antennas were

accurately spaced 1,500 meters apart on a flat dry lake bed. By

varying the position of a transmitter over a path which half-way

encircled the two antennas, the phase difference between the two was made to change. The wavelength of the radio waves was then

calculated by dividing the accurately known distance between the

receiving antennas by one-half the total change in phase difference.

2.15. Radio Propagation Engineering

The ultimate objective of NBS work in radio propagation

engineering is the more efficient use of the radiofrequency spectrum.

This objective can be attained only to the extent that the nature

of radio-wave propagation, together with the characteristics and

effects of radio noise and interference upon various signals, are
known qualitatively and quantitatively. The program is directed

generally toward solution of radio-wave-propagation, radio-noise,

and signal-to-noise problems. Quantitative sludy of these phenomena includes: (1) the collection of statistical samples of data

appropriate for their description; and (2) development of suitable

methods for predicting, from the samples, the statistical characteristics of the variables required for engineering applications.

Among the projects directed toward this objective were basic

radio studies, modulation studies, terrain effects on propagation,

tropospheric effects on propagation, design of an airborne micro- wave refractometer, and phase-stability studies. A new project on sporadic E was initiated for studying the efficient use of the

25- to 60-Mc portion of the spectrum.

Radio-Noise Studies and Noise Predictions. A complete revision

of existing worldwide radio-noise predictions has been undertaken,

including the preparation of new noise grade maps and prediction

curves. During the meeting of the International Scientific Radio

Union at The Hague in 1954, a preliminary report on these new

noise predictions was presented to a group representative of the

International Consultative Radio Committee (CCIR) concerned

with radio-noise predictions. This group recommended that a representative of the Department of Scientific and Industrial

Research of England come to the Boulder Laboratories to work

with NBS personnel in finalizing these predictions for use by the

CCIR. As a result, agreement has now been reached on the type

of presentation to employ and the weight to be attached to the

various measurements that form the basis for the revised noise

grade maps.

Planning was begun for a radio-noise recorder to be operated in the Antarctic during the International Geophysical Year, after

information on requirements for such an installation had been

submitted to their planning staff. It is expected also that a large

number of the new NBS noise recorders will be in operation

throughout the world during the International Geophysical year

in 1957-58.

A detailed statistical study of the amplitude and time distribution of atmospheric radio noise has been undertaken to permit more accurate evaluation of errors produced in various radio sys- tems by atmospheric noise. Equipment for making these cumula108
This 500-foot tower at Haswell, Colorado, shown at left is used in studying

"tropospheric scatter propagation", the transmission and reception of VHF

and UHF signals beyond the line-of-sight. Data for worldwide radio noise

predictions are obtained from field recording stations like the one at ri£ht

located near Boulder, Colorado (p. 108).

tive amplitude and time distribution measurements has recently

been completed and is undergoing preliminary tests in the verylow-frequency range. Preliminary results indicate that the communication efficiency of many existing systems can be considerably

improved, and that it may be possible to predict the optimum

communication capacity for a radio channel contaminated with

atmospheric noise.

Tropospheric Forward Scatter Propagation. In the past few

years it has been determined that useful VHF and UHF trans- missions are not limited to the radio horizon as was previously

believed, but can provide reliable service at distances far beyond

the line-of-sight limit. This phenomenon, called "tropospheric

forward scatter propagation," is believed to result from scattering

of radio waves by very small inhomogeneities in the refractive

index of the atmosphere. Reliable transmission to distances of

approximately 400 miles has been demonstrated, using high-power

transmitters and directional antennas. Both industry and the

armed services have begun to use tropospheric scatter for new and

existing communication circuits with consequent savings through

the elimination of many relay stations.

Radio scattering received increasing attention during 1955. An

investigation of tropospheric scatter propagation characteristics

utilized a chain of five receiving stations in Kansas and eastern

109
Colorado. These stations automatically record the field strength

of five VHF and UHF transmissions originating from NBS experimental transmitters located on mountains near Colorado Springs,

Colorado. The investigation has also included a meteorological

measurement program centered chiefly around a 500-foot tower at the Haswell (Colo.) receiving station. This tower includes micro- wave refractometer facilities to measure fluctuations of the refractive index of the atmosphere for the purpose of correlating meteorological parameters with radio field strengths. Some progress has

been made in developing an appropriate theory of scatter-tvpe

propagation and methods for predicting the reliability of this mode

of propagation.

Phase Stability of VHF and UHF Transmissions. A project was

began to determine the phase stability of received VHF and UHF

transmissions, or the variation of electrical path length over

line-of-pight paths. The project required development of techniques and equipment capable of measuring very small changes in the phase and amplitudes of the received field. This type of

measurement should prove very useful in further investigation of

tropospheric-scatter propagation and should lead to a better

understanding of atmospheric turbulence.

Obstacle Enhancement of Signals. Enhancement of radio trans- missions by obstacles was investigated in a short but extensive

program. Transmissions in the VHF and UHF band over and

adjacent to mountain obstacles (including Pike's Peak) demonstrated that the phenomenon exists and correlates quite closely with

knife-edge diffraction theory. Obstacle enhancement of signals has

been demonstrated to be of practical value and has been adopted

by the armed forces for certain communications circuits.

2.16. Radio Standards

The program in radio standards is concerned primarily with

electrical primary standards, measurement techniques, and properties of matter in the frequency range from 30 kilocycles through

the highest available microwave frequencies. In the extreme

high-frequency ranges, standards and adequate measurement

techniques are essentially nonexistent. In the lower frequencies,

increasing electronic applications have created a need for greatly

improved primary standards and calibration techniques.

110
Power Measurements.—A self-balancing d-c bolometer bridge for high-precision bolometric power measurements at microwave

frequencies was developed and placed in operation. The bridge

is expected to have wide application in making accurate microwave

power measurements and, in modified form, to other kinds of

microwave measurement. The bolometric technique, by means

of which the heating effect of rf power is compared with that of a measured amount of d-c power, is extensively used at low power

levels for the measurement of UHF and microwave power. Much

of the research effort expended in power measurement during the

past few years has been directed towards the determination of

bolometer mount efficiencies or evaluation of the validity of the

rf-d-c substitution principle. The only accessory instrument of

sufficient accuracy to utilize the results of these investigations has

been a manually operated d-c Wheatstone bridge. The self- balancing d-c bolometer bridge extends both the accuracy and

dynamic range achieved with the manual technique, and provides

the additional feature of a large measure of operational convenience. The self-balancing feature was achieved by using a d-c

amplifier of exceptional gain with freedom from zero drift. A

constant-current generator and differential current measuring

circuit provide means for extending the dynamic range of the

bridge.

For accurate rf power measurements highly stable and frequencyinsensitive loads are necessary. In the 50-ohm range, the Bureau

developed loads of this type which, by proper choice of materials

and design features, can be made with negative, positive, or nearzero temperature coefficients of resistance. For example, some of

the loads have temperature coefficients of less than 1 part per

million per degree C and show good stability up to the melting

point of the solder used (about 170° C).

Voltage Standards. Considerable progress was made in developing reliable voltage-transfer standards. Units employing piston

attenuators and thermoelements proved to be stable to d= 1 percent

over a period of a year or longer at frequencies up to 300 megacycles per second. Tests and applications of these units at fre- quencies up to 600 megacycles per second proved them to be the

most stable and most efficient devices to date for calibration work.

Ill
Attenuation Standards, xA.ttenuation standards are in general

necessary to all other precision radio measurements. During the

year, two new standard piston attenuators were put into operation

and tested for performance. Theoretical analysis of a new type of

insertion loss and phase measuring system was continued and developed to a much greater generality. Results showed the system

to be self-calibrating. A simple and accurate method was devised

to determine the constants of the system. Very-high sensitivity

and accuracy are potentially possible but place rather stringent

performance requirements on auxiliary equipment. Some work,

which is continuing, was done to meet these requirements.

Coaxial Resonance Line for Microwave Impedance Measurements.

A 50-ohm coaxial resonance line (Chipman type) was developed to make precise measurements of impedance, voltage standing-wave

ratio (VSWR), and reflection coefficient at frequencies from approximately 300 to 18,000 megacycles per second. This instrument

represents an advance over present methods of microwave impedance measurement primarily because its internal cross-sectional di- mensions are the same as those of the type N connector in which it terminates. This eliminates discontinuities between the measuring line and the load, improving the potential accuracy and the

convenience ot measurement. The small diameters of the line also

make it possible to operate over a wider frequency range than has

heretofore been practical with a single impedance-measuring instrument. The lower frequency limit is determined by the maximum

permissible length of unsupported center conductor, and the upper

limit by the cross-sectional dimensions which determine the cutoff

frequency for higher mode propagation. A unique mechanical

feature is the small diameter of the coaxial feed line which transmits

microwave power from the tiny loop, located in the short-circuiting

piston, to the detector output connector. The feed line was difficult to construct because of its unusually small size (outer diameter,

0.050 inch). With this instrument it will be possible to make coaxial impedance measurements over a wide range of microwave

frequencies with an accuracy exceeding that obtained with con- ventional precision slotted lines. Precision Microwave Interferometer. A project has been undertaken to measure the velocity of light to greater accuracy than ever

before. The measurement is to be made in terms of the frequency

112
and free-space wavelength of millimeter waves. The velocity of

electromagnetic waves will be calculated as the product of these

two quantities. The wavelength measurements will be made with

a precision microwave interferometer now being developed for the

purpose. This instrument may also be used for very accurately

measuring the lengths of such standards as meter bars and geo

detic tapes. For this purpose, the velocity of light can be regarded

as fixed, and the measured lengths can be expressed in terms of this

constant and an accurately known frequency. Like the NBS

mercury 198 lamp, the microwave interferometer offers a means of

placing length measurements on an atomic basis. If the necessary

frequency were to be derived from an atomic clock, the length

measurement would be based wholly on the unchanging properties

of atoms.

The interferometer under development is analogous to an optical

interferometer. It is designed to measure wavelengths by giving

a null on a meter whenever a reflecting body is moved a distance

of one-half wavelength. It will thus provide a length standard

with graduations every few millimeters. Theoretical studies indi- cate that measurements with an accuracy exceeding one part per

million may be possible. Increased accuracy may be expected as technical advances permit the microwave frequency to be increased.

Dielectric and Magnetic Materials. The physical and electrical

properties of dielectric and magnetic materials are widely used in the design of nearly all electrical, electronic, or radio equipment.

Accurate measurements on these materials are essential for improving the design of equipment, fabrication of materials, and

development of structure theory. During the year a cavity was

completed which will measure the dielectric properties of solids

and liquids at the lower radiofrequencies. This cavity operates

automatically and can be used in the range from direct current

to 1,000 megacycles per second and at temperatures from —40° C

to 500° C.

An improved temperature-coefficient permeameter was constructed. With this device, temperature coefficients as low as 3X10~6 per degree centigrade can be measured for a material

with permeability of 10. A method was developed for making

permeability and loss measurements in the range of 50 to 300

megacycles per second with the rf primary standard of permeability.

L13
Portable antenna and mobile recording equipment for studying obstacle enhancement of radio signals by mountain peaks. The equipment is shown

installed in the Arkansas River Valley south of Pike's Peak, Colorado (center

background). This is a direct line over the top of the peak from transmitters on Lookout Mountain near Denver (p. 110). Microwave Spectroscopy of Gases at High Pressure- The Bureau

continued a systematic study of the microwave absorption of gases

at pressures from to 60 atmospheres and frequencies from 1,000

to 24,000 megacycles per second. Principal objectives of this

project are: (1) to obtain a better understanding of the dielectric

behavior of matter through a systematic investigation of gases at progressively higher pressures; (2) to make definitive tests of

spectral line-shape theories; and (3) to employ pressure broadening

as a sensitive tool for studying molecular interactions in gases. The absorption in oxygen arising from the presence of a small

magnetic dipole moment was investigated in detail up to about

40 atmospheres (600 pounds per square inch). The absorption

consists of two parts: a nonresonant or Debye-type contribution

and a resonant contribution centered near 60,000 megacycles per

second. The nonresonant contribution, which had not been

subjected to prior investigation, predominates at the lower micro114
wave frequencies and is therefore of considerable interest to those

studying atmospheric attenuation of radio waves. At pressures

up to about 10 atmospheres the resonant contribution is consistent

in magnitude with predictions based upon existing line-shape

j theory and line-width data. At higher pressures, however, the

resonant frequencies begin to decrease toward zero, and the spectrum undergoes a transition from resonant to nonresonant in a manner analogous to that previously noted for ammonia and

deuterated ammonia. While only nonresonant absorption is generally observed in liquids, so that such transitions are to be

expected in going from the gaseous to the liquid state, it is noted

that the changes to liquid-like behavior can occur long before the

molecular density approaches that of the liquid.

Measurements of the nonresonant absorption in a number of

symmetric top molecules, such as the methyl halides, were completed. Because an adequate theory of nonresonant relaxation

times in gases is lacking, considerable effort was devoted to the

theoretical aspects of the problem.

Further measurements of absorption in the nonpolar gas, carbon

dioxide, substantiated earlier work. Absorption is not ordinarily

expected for nonpolar gases in the microwave region, and a search

for this effect in other nonpolar molecules is in progress. Atomic Standards of Frequency and Time. Work progressed on

an ammonia-beam oscillator to be used as an atomic frequency and

time standard of high accuracy. This system is patterned after

the ammonia-beam oscillator recently developed at Columbia

University. Experiments at Columbia have shown a precision

of 1 part in 600 million, achieved with simpler equipment than is used with either the Bureau's ammonia-absorption clock or cesiumbeam clock. The NBS oscillator should prove helpful in the

effort to reach an atomic basis for frequency and time standards.

Frequency Standards and Standard Frequency Broadcasts. Fre- quency is measured more precisely than any other physical quantity. Its accurate measurement is highly important in using

efficiently the limited radiofrequency spectrum to serve the ever

increasing radio-communication requirements. During the year

the national standard of frequency and time interval was transferred from Washington, D. C, to the Bureau's new facilities at

115
Boulder, Colorado. Assessment of the transferred groups of

standards was begun on July 7, 1954, and by means of the broadcasts from WWV, their performance and rates were determined to the required precisions by October 12, 1954, whereupon the transfer

of the National Standard was completed. Three quartz resonators were placed in separate 50-ft wells to provide temperature stability.

The Bureau's two radio stations, WWV (Beltsville, Md.) and

WWVH (Maui, T. H.), continuously broadcast standard radio and

audiofrequencies, standard time intervals, time signals, standard

musical pitch, and radio propagation disturbance warnings to the

world. Several improvements were made during the year. For

example, at WWV single sideband broadcasts on five carrier fre- quencies (2.5, 5, 10, 15, and 20 Mc) were initiated, using the

upper sideband. Better identification of the minute interval was made possible by adding a double pulse marker (spaced 0.1 second)

each minute. The tone modulation was removed for precisely

40 milliseconds each second; during this quiet period the seconds

pulse was broadcast so as to mark more effectively each seconds

pulse for many uses, e. g., in automatically recording the occur- rence of an event to a few milliseconds. Because supplementary

services may be needed at low frequencies to transfer a more

accurate standard, work was initiated to study the accuracy of

low-frequency broadcasts as received.

Recording was begun of the frequency of WWV and WWVH

at 5, 10, and 15 megacycles per second as received at Boulder.

Preliminary analysis of the records indicates that Doppler fre- quency errors of 3 to 4 parts in 108 occur over these paths at certain times. Theoretical expressions were derived relating the

rate of change of ionosphere-layer height to the fractional fre- quency error for given path length and mean layer heights. These

derivations gave a fractional error of 1.3 parts in 10s for the

WWV-to-Boulder path when the rate of change of layer height was assumed to be 25 kilometers per hour. Apparently the vertical velocity of the layer exceeds the value assumed at certain

times of the day. Careful study of this phenomenon will have

an important bearing upon the possible use of low-frequency broadcasts for very accurate frequency standards available through radio

communication.

116
2.17. Basic Instrumentation

The Office of Basic Instrumentation was established in 1950

to serve as a research, reference, and consultation center on problems of instrumentation for the laboratories of Government and

industry. This program, sponsored by the Office of Naval Research, the Air Research and Development Command, the Atomic

Energy Commission, and the National Bureau of Standards, represents an effort to utilize the Bureau's facilities and experience in the field of physical measurements to advance those techniques

of measurement and control that are fundamental to progress in science and industrial technology.

Modern developments in instruments and instrument systems

must employ principles and concepts from such diverse fields as

electronics, mechanics, thermodynamics, optics, chemistry, materials, and atomic physics. The purpose of the Office of Basic

Instrumentation is to bring together the specialized knowledge and

skills of the Bureau staff* in these fields for the solution of measure- ment problems. It also endeavors to encourage and stimulate

research and development throughout the nation on measurement

devices and techniques. And it maintains active familiarity with

technical progress in other measurement laboratories, in order to

fulfill its responsibility as technical consultant to Government and

industry on instrumentation.

In furtherance of these objectives, the Office of Basic Instru- mentation cooperates with other Government agencies in arranging conferences and symposia in areas of special interest or of

rapidly developing importance in the field of instrumentation. It also cooperates with technical societies in promoting instrumentation progress. These activities often help to define areas of instrumentation in which research and development work needs to be

done, either at NBS or elsewhere.

In all phases of the program, emphasis is on the basic fundamentals of measurement and control and on development of the

science of instrumentation. Those research projects are favored

which seem likely to have broad utility in measurement or to extend significantly the range, reliability, or sensitivity of some

general class of instruments. Also of basic importance are theoretical and experimental studies of problems common to many

117
instruments—such as drift, lag, unsteadiness—or of the limits of

performance inherent in various types of instruments.

Because the output of any sensing element is a signal, studies

of problems in handling signals may be carried on profitably on a quite general basis, without regard to particular types of measurement. Areas in which such general studies are encouraged include

amplification, loss of information in transmission, analogue-todigital conversion, indication or display, recording, separation of

measurement signals from extraneous signals or noise, automatic

data correction or reduction, automatic computation, and automatic control.

The technical work of the Office of Basic Instrumentation has

two principal objectives: (1) Systematic analysis of available

methods and devices in terms of their performance and characteristics, and (2) research on new applications of principles and

materials leading to the development of instruments and techniques

not now available. This program is carried out largely through

the assignment of instrumentation research projects to those NBS

laboratories that are best qualified to conduct research in the

particular field of science involved. The Office of Basic Instru- mentation also maintains a small laboratory staff for investigation

of special problems and a group of specialists in instrumentation

literature who are developing a reference and consultation service

to aid in the solution of instrumentation problems.

Specific Instrument Developments. Projects included in the basic

instrumentation program in the past year have been conducted in seven of the technical divisions of the Bureau as well as in the

Office of Basic Instrumentation itself. Among the accomplishments of the projects carried on in the technical divisions have

been: the successful construction of an extremely sensitive calorimeter for measuring the power in an X-ray beam (page 32); the

completion of a preliminary model interferometer using pulsed

illumination for measuring vibration amplitudes; design of several

high-speed counting circuits for use in computers based on the

diode amplifier (page 96); the construction of an instrument for direct measurement of dynamic bulk modulus; and an improved

infrared spectrometer that will operate at 130 microns.

118
Hand-operated indexing equipment used with the NBS instrument reference

service. Apparatus consists of: A set of index cards (foreground), manually

operated punch (center), and a plastic reading illuminator (background).

Insert: Descriptive drawing of index term cards showing "peekaboo" method

of reference classification. Work conducted in the Office of Basic Instrumentation laboratory is generally confined to those cases where the need is felt for exploratory studies by a versatile group specializing in instrumentation. When such an activity is seen to merit a full scale

project, it is turned over to the proper technical division for further

work. Selected projects conducted in the Office of Basic Instru- mentation laboratory are discussed below.

Instrument Reference Service. The field of instrumentation has

only recently emerged as a new and rapidly expanding coordination

of knowledge from a variety of previously existing fields. Both

the newness and the rapidity of growth of instrumentation have

posed burdens on those desiring to keep abreast of instrument

developments. Scientists in Government and industry alike need

to have convenient, rapid, and thorough access to instrument

information. The major obstacles are the inadequate coverage of

instrumentation information provided by existing abstracting and

indexing services whose main interest is the information obtained

by use of the instrument and the nonexistence of efficient classi- fication systems for instrumentation. These considerations have

led to the establishment of an instrument reference center whose

119
objective is to improve accessibility of instrument information in four ways: (1) by developing improved systems for storage and

retrieval of information; (2) by fostering developments elsewhere

which will make instrument information more readily available;

(3) by surveying specific developments in instrumentation; and

(4) by providing consultation services in instrumentation.

Indexing System. Consideration of the various ways in which

the problem of classification has been approached in the past led

to the recognition of the basic "multidimensional" nature of human

knowledge. The concept that information might be located in a system of "coordinates" by the interaction of a number of identifiying terms was studied, and it was concluded that this approach was a desirable one for this specific application. A set of 10

dimensions and corresponding terms within the dimensions was

selected to provide the framework of the classification system.

In the system there is one card for each descriptive term instead

of one card for each document as in conventional library catalogues.

The work of classifying instrument information for indexing is under way. Routine coverage has been extended to 12 current

journals and will be augmented as additional analysts are hired.

Analysis is performed by full-time analysts of the Office of Basic

Instrumentation and by "contributing analysts," NBS staff members who are experts in various fields. A study has been made to estimate the number of instrument

articles to be expected in a year and to determine which of the

scientific publications merit routine coverage. The study indicated that coverage of some 137 publications would be desirable

and that this would provide some 15,000 instrumentation references

per year. The reference and consultation services are being used more and more with the number of consultation questions exceeding the

number of reference questions. Questions are answered on the

basis of information obtained by using the new system supplemented by other literature search techniques for earlier literature.

Consultation with authorities is also made when needed. A pre- viously prepared report, "Guide to Instrumentation Literature,"

has been revised and is being prepared for publication as an NBS

Circular with the title, "Instrumentation Literature and Its Use."

120
The usefulness of the previous edition had been shown by the

considerable demand for it, and it is believed that the revision

will be of still greater value because of the addition of indexes

and the greater coverage it provides

Instrument Surveys. Surveys of various areas of instrumentation are conducted in order to provide systematic analyses of

available methods and devices in terms of their performance and

characteristics. The surveys fill a need generally felt by those

charged with planning or conducting research and development on

the devices or in areas where they will be needed. As with other

portions of the basic instrumentation program, some of the sur- veys are conducted by the staff members of the technical divisions

while others are conducted by the Office of Basic Instrumentation.

Two surveys in the basic instrumentation program, made by

members of the Mechanics Division, have recently been completed and reports issued. One was the Survey of Dynamic Pressure Instrumentation and the other was the Survey of Stress- Strain Recorders. Surveys which have been under way in the

past year in the Office of Basic Instrumentation are: (1) Survey

of Thickness Measurements, (2) Survey of Recording Methods and

Instruments, and (3) Survey of Recent Developments in Flow

Measurement. The last named has been completed.

Studies on Shock and Vibration. The need for the measurement

of vibration over wide ranges of frequency and amplitude has

grown with the use of higher speeds presented by jet and rocket

propulsion and with the use of stiffer structures which must be

operated under greater stress. In order to assay the effects of

vibration it is necessary to provide suitable transducers and means

of calibrating them. The Office of Basic Instrumentation has

contributed in this area through work on methods for the design,

construction, and calibration of piezoelectric accelerometers.

A system was designed and built for calibrating vibration pickups

over the broad frequency band from to 50,000 cps. The system

includes a piezoelectric vibration generator to provide vibrations

in the desired range. The amplitudes of the vibrations provided

by the generator are detected by means of the resonant bridge

carrier system, which measures changes in electrical capacitance

caused by motion of a steel plate attached to the generator. A

resolution of 10~9 inch is attainable.

121
A jerkmeter for studying human heart action is shown partially assembled.

When a barium-titanate piezoelectric element is distributed by the forces generated by the patient's blood flow, strains are developed in the element

which cause it to produce an electrical signal.

A device known as a jerkmeter has been developed to serve as a prototype for use in ballistocardiography Its output is proportional to the derivative of acceleration (jerk). Other activities in the shock and vibration field include the construction of pre- liminary models of high-frequency, high-acceleration, low-cost

accelerometers using thermosetting casting resins, the development of a test procedure for the evaluation of low noise electrical

cables, extension of previously available curves for the effect of

Coulomb and viscous damping on mechanical vibration, and the

design of a large barium titanate accelerometer for use in shockvelocity measurements.

3. Calibration, Testing, and Standard Samples

The calibration and standard samples programs, stemming from

the Bureau's custody of the Nation's basic physical standards,

provide a unique service for Government, industry, and the

general public. The testing program on the other hand is confined

almost entirely to serving other Government agencies in connection

with their purchasing, regulatory, or functional responsibilities.

In providing standards of measurement for the Nation, the

Bureau makes available the basic standards and encourages those

requiring such standards to make their own comparisons and

calibrations. Government agencies, industrial firms, and scientific and educational institutions now have need for such a large number

122
and variety of standards that the Bureau, with its limited resources, can provide, in most cases, only the master standards.

3.1. Calibration Center

The new Calibration Center that is being developed at the NBS

Boulder Laboratories illustrates how this policy is being implemented. The principal impetus for creation of the Calibration

Center grew out of the urgent need by the Air Force and the Navy

Bureau of Aeronautics for accurate calibration of the vast quantity

of radio, radar, and other electrical equipment that accounts for more than half the cost of some modern military planes. Thus

the Bureau will set up the necessary primary standards, d-c as well as radiofrequency through microwave, and will calibrate

transfer standards provided by the Air Force and the Bureau of

Aeronautics. These transfer standards will then provide the

different air and naval depots with means for calibrating their

working standards. The aircraft operating instruments in turn

will be checked against these working standards.

The Congress recently appropriated $765,000 to construct a new

wing of the Radio Laboratory to house this operation. Space will be provided both for the calibration laboratory operated by NBS

personnel and for a depot at which Air Force and Bureau of Aeronautics personnel will receive and perform the necessary maintenance on their transfer standards prior to calibration, and from

which these standards will be shipped to the different depots.

The Calibration Center is expected to be in operation about

January 1, 1957. Its services will, of course, be available to other

military agencies and to the public. Development of the necessary

primary standards for this service constitutes a major project in

itself, since some of them lie in fields in which no standards have

as yet been constructed.

3.2. Making Standards Available for Practical Use

Time and Frequency . The ideal solution to the problem of

making standards available to all who need them is most nearly

realized in the case of standards of frequency and time that are broadcast continuously by the Bureau's radio stations—WWV at

Beltsville, Maryland, and WWVH in Hawaii. These stations

367607—55 9 123
provide standards of radiofrequency at 2.5 , 5, 10, 15, 20, and 25

megacycles per second. Also, on each carrier frequency is broadcast a 600-cycle standard audiofrequency for controlling the

generation of 60-cycle current in the electric power industry, a 440-cycle standard musical note, and precise seconds signals.

These signals are received and widely used to check continuously

or periodically the standards of the radio-electronics industry,

aircraft and ship navigators, research laboratories, armed forces,

broadcast stations, and utilities. During the past year the direct calibration of equipment at radiofrequencies was materially interrupted by the move of

laboratory facilities from Washington to Boulder, Colorado.

Seventy-six items of apparatus used for laboratory standards were tested or calibrated including frequency meters, attenuators,

inductors, and dielectric and magnetic samples.

Clinical Thermometers. Clinical thermometers afford a more

typical illustration of the way in which a national standard of

measurement maintained by the Bureau is translated into practical use for the benefit of the public (see diagram on page 125).

The basic standard in this instance is the International Temperature Scale maintained by the ice, steam, and sulfur boiling points.

These points, experimentally realized with elaborate procedures,

are used to establish the scale of a specially constructed platinum

resistance thermometer which is taken as the primary standard of

temperature. Mercury-in-glass thermometers of suitable construction are then calibrated against the resistance thermometer

and are used in turn as secondary standards for testing clinical thermometers.

As shown in the diagram two other groups are concerned with

the testing of clinical thermometers. The manufacturers test their output before it goes on the market, and, where the sale is controlled by law or regulation, certain State and local authorities

test clinical thermometers from the open market. The Bureau

makes tests for other Government agencies and for the public.

When large purchases are made the Federal Government tests are made on a sample, usually about 10 percent from each lot, and

from the results the quality of the lot as a whole is ascertained by

statistical means.

124
International Temperature Scale fixed by

ice point, eteam point, and sulfur boiling point

Primary Standard

(accurate to 0.002 deg ¥) Platinum Reel stance Thermometer

Secondary Standard

(accurate to 0.02 deg F) Mercury- in-glass Thermometer

Manufacturers

Test5output for compliance with

Dept. of Commerce Commercial Standard

1-52

Veterans Administration

Test lO^Ei of sample

of all thermometers purchased

State and Local

Weights and Measures

authorities

Public

as requested 5

Test

open market

Diagram illustrates how the international temperature scale maintained by

the Bureau is translated into practical use for the benefit of science, industry,

and the public. Photograph shows thermometers are being calibrated

against a "standard" liquid-in-glass thermometer. During 1955 the Bureau

calibrated over 33,000 clinical thermometers.

125
In the past year 33,110 clinical thermometers were tested by the

Bureau; 31,911 of these represented a sampling of over 365,650

thermometers purchased by the Veterans' Administration. The

fact that only about 1,000 thermometers were tested for the public

indicates that there is no longer any large scale demand for the

testing of individual thermometers by the Bureau.

The diagram shows that, as in all calibration, there is a loss in accuracy at each stage of comparison from the primary standard

to the end object. In order that the clinical thermometer may

have the accuracy of 0.2° F that is commonly required, it is neces- sary that the standard thermometer against which it is compared

be accurate to 0.02° F, and that the scale of the primary standard

resistance thermometer be established to 0.002° F. Commercial

Standard CS 1-52 to which clinical thermometers are commonly

made is a standard established by manufacturers and users under

a procedure of the Department of Commerce. In addition to the

accuracy, it covers the construction, the ease of shaking down, and

the permanence of the markings.

Dental Materials. Still another way of making standards available is through codes and specifications. For example, in connection with the maintenance of the List of Certified Dental

Materials of the American Dental Association, Research Associates

of the Bureau tested 81 samples of dental materials for compliance

with ADA Specifications. These samples included investment materials, wrought gold wire alloys, silicate cements, hydrocolloidal

impression materials, denture base resins, and mercury. The

Association, through the Journal of the American Dental Association, made available to practicing dentists a certified list of 315

items of dental materials.

3.3. Calibration Requests Show Industry Trends

Several trends in the types of tests requested indicate changes in emphasis in the electrical industry. For example, the increase in the number of standard cells of the saturated type that are submitted indicates that greater importance is being attached to the

accuracy of measurements. The saturated cells assure a much

more stable voltage, but must be used in a thermostated enclosure

and hence are less convenient to use than the unsaturated cells which have a lower temperature coefficient.

126
Another trend is toward the use of higher frequencies. Because

of the increasing use of 400 cycle power for aircraft and for computer applications about 20 percent of the requests are for tests at this frequency. Meanwhile, requests for tests at 25 cycles are very infrequent. A few tests are requested at 800 and 1,000 cycles

but most of the remainder are at 60 cycles.

There is also a growing industrial interest in the use of reactors and capacitors as power factor standards for the production testing

of similar units used in power transmission systems. Because the

phase defect represents a continuous loss of energy, once these

static devices are connected to a power line for protective or power-factor purposes, small gains that reduce power losses are

desirable. Thus the Bureau was called upon for measurements

on a large reactor and a capacitor in order that these units might

be employed as standards.

There has been an increase in requests that the Bureau report

additional significant figures in the calibration of resistors, volt

boxes, voltage transformers, and other electrical instruments.

Experience with instruments that are returned for periodic cali- bration indicates that progress in manufacture has improved the

stability of the instruments to the point where it is now feasible

for the Bureau to make calibrations to higher orders of precision.

Several new and useful instruments tested by the Bureau for

the first time included (1) a strain-gage "calibrator," (2) a Standard Ratio Transformer, an autotransformer arrangement that provides a 5-decade division of the supply voltage, and (3) a product

resolver, an unusual adaptation of wattmeter elements. All were

found to be in rather good adjustment and each represents a useful

contribution to the technology of measurements, the calibrator

for use in strain gage work, the ratio transformer where accuracy

of a-c voltage subdivision is important for computer applications,

and the product resolver where the accuracy of analog products

must be verified.

3.4. New Standard Samples

One new standard sample of metal—a heat-resisting jet-engine

alloy—was added to the standard samples program through which more than 500 materials of certified properties, purity or composition are available to science and industry (NBS Circular 552,

127
Standard Samples and Reference Standards issued by the National

Bureau of Standards). Other new standard samples of metal had

been requested but the Bureau's available resources were used in renewing 10 standards of composition that had become exhausted;

there were 5 steels, 1 bronze, 2 cast irons, 1 arsenic trioxide, and

1 acid potassium phthalate. Two new standard samples of rubber

compounding ingredients were established and two reference lots of synthetic rubber that had been established by the Office of

Synthetic Rubber were taken over by the Bureau when the Government-operated plants were sold to private industry. The

standard sample of dyed paper, established late in 1954 and

designed for use in calibrating carbon arc lamps for use in fading

and weathering tests, was quickly exhausted and was replaced

with a new lot. The metallurgical laboratories have undertaken to supply metals,

in appropriate form of wire, sheet, rod, or solid pieces, that will be certified for physical properties rather than for chemical composition. A supply of suitable metals is being accumulated and

the necessary instrumentation is being developed. One instrument, for example, for this program is a high-sensitivity dilatometer to define temperature-structural change characteristics.

Other developments include improved equipment to determine

electrical resistivity versus temperature characteristics.

During the year a total of 32,501 standard samples were issued,

representing a fee value of $136,784.30. Of the more than 200

standards of certified composition or purity available, about

24,100 samples, with a value of $104,000, were issued. A total of

3,752 samples for rubber compounding and 392 samples of cali- bration paper were issued at a total value of $10,672.60.

3.5. Testing for Government Purchase

The Bureau tests a wide variety of products purchased by the

Federal Government for compliance with Federal Specifications.

In a few instances tests by the Bureau control a large part of the

procurement by civilian agencies. Testing is done for the public

only in unusual cases when the Bureau has facilities or equipment

not available elsewhere.

Government contracts for electric lamps which are purchased in large quantity are awarded to suppliers who have passed quali128
ncation tests conducted by the Bureau. A staff member conducts

tests in the manufacturers' laboratories and takes samples from

lots of lamps set aside for Government purchase for additional tests at the Bureau. These tests are applied not only to incandescent

lamps but also to fluorescent lamps, photographic flash lamps, and

many other types. The lamps tested by the Bureau are representative of purchases amounting to about 3 million lamps of which

only 7 percent are rejected. While this testing is done exclusively

for the Government it benefits the public indirectly. Precautions

that are found necessary to produce lamps that satisfy Federal

specifications are in general applied to the entire output of a factory.

The only reliable tests for dry cells require a great deal of time.

To overcome this difficulty, a plan has been in operation for many

years whereby tests on dry cells from all suppliers desiring Government contracts are conducted continuously. Thus the contract

for any given year is awarded to a supplier whose product has met

the requirements during the previous period.

The quality of cement purchased by the Federal Government is important because much of it is used in dams, locks, monumental

public buildings, and other structures that are designed for high

strength and very long life. The Bureau conducts acceptance tests on a considerable part of this cement and maintains laboratories

for this purpose in Allentown, Pa., Denver, San Francisco, and

Seattle as well as in Washington, D. C. From time to time

laboratories are established temporarily in localities in which a

large amount of construction is in progress. Considerable economy

to the Government is effected by arranging with the producers in certain areas to set up large bins of cement which are tested and

sealed for use by any Federal agency that may require cement.

In 1955 about 30,000 samples were tested, representing approximately 15 million barrels of portland cement. In addition, tests were made on 5,800 hardened concrete specimens and on 750

aggregates. In localities where the service was not available from

other agencies the engineering properties of 500 soil samples were

determined.

Closely related to the cement testing program is the Cement

Reference Laboratory, located at the National Bureau of Standards, and jointly supported by NBS, the Bureau of Public Roads,

129
the Army Corps of Engineers, and the American Society for

Testing Materials. This Laboratory provides a voluntary inspection service for maintaining uniform standards in cement testing

throughout the country. On request its staff visits laboratories

to make a careful evaluation of their facilities, and equipment,

and the qualifications of their staff. Reports are made only to the laboratories inspected. In 1955 seventy cement laboratories

availed themselves of this service.

At the request of various Government agencies, the Bureau

tested a wide variety of building materials. Examples include

tests of fire and weather resistance of structures and materials,

heating and cooling systems, thermal insulation materials for both

underground and above-ground installations, heat and water vapor

transfer characteristics of insulating materials, elevator buffers,

and concrete masonry walls.

Tests were also performed on such items as: marble, slate, sewer

pipe, brick, fire-retardant paints, plastic glasses, fire extinguishers,

flush valves, air filters, portable air conditioners, insulated food

containers, and bituminous materials.

3.6. Services in Other Areas

Services in specific areas not discussed above are summarized in the following paragraphs.

The Bureau regularly calibrates surveyors' tapes for the Coast

and Geodetic Survey and for the Inter-American Geodetic Survey.

These tapes are of invar and are used to establish baselines which

are used as bases for our geodetic surveying. A complete calibration includes the determination of the coefficient of thermal ex- pansion.

It is now common practice to make contour maps for road

building projects, hydroelectric installations, and general topographic purposes by the application of photogrammetric methods

to airplane photographs. If satisfactory maps are to result, the

photographs must be of good quality and free from distortion.

Testing methods developed at NBS are regularly applied each

year to a large number of airplane cameras designed for photogrammetric applications submitted by other Government agencies

and the public.

130
The Bureau's new Gamma-Ray Laboratory was built to meet the growing

demand in medicine, industry, military and civil defense for gamma ray standards and calibration. Here, a radiation survey instrument is being

adjusted before exposing it to gamma rays from a 200-curie cobalt-60 source. Nearly a thousand radioactive standard samples were issued

during the year. In addition, 491 cobalt-60 sources totaling 10,222

millicuries were calibrated, and 839 radium sources totaling 18,155

milligrams were calibrated and certified. Six standard NBS

Mercury-198 lamps were distributed to laboratories approved to receive them. Chemical and isotope analyses of 492 samples were reported. Also 750 items of radiological equipment were

calibrated. Increasing use is being made of neutron sources and

six sources were calibrated together with 2 thermal-neutron dosimeters and 4 fast-neutron meters.

About 2,500 samples of paints and varnishes, soaps and detergents, metals and alloys, raw sugars, and reagent chemicals, were

analyzed or tested for compliance with purchase specifications or

in connection with research projects or regulatory investigations.

This number includes about 350 samples submitted by the Atomic

Energy Commission for umpire analysis to settle disagreements

between the Commission and suppliers of materials.

A standardizing service essential to the use of "magne gages"

is provided in the form of specimens of plated metals with coatings

of certified thickness. Some 5,540 of these standard samples were

131
issued. Five benzoic acid thermometric standards were issued,

bringing to 101 the total of these calibrating devices issued since

this service was begun in 1947.

As a special service for the Veterans Administration 2,400 dilution pipets were marked with the observed dilution ratios. These

were to be distributed as reference pipets to the hospitals and

clinics operated by the Veterans Administration.

Tension, compression, bending, torsion, hardness, and other

mechanical tests were made on a variety of specimens submitted

by other Government departments, State institutions, and private

organizations to determine mechanical performance and compliance

with specifications. Specimens included reinforcing steel, copper

conductors, wire and fiber rope, hand tools, pole top pins, crossarm

pins, upset spool bolts, insulator wire holders, pencils, signal flares,

file cabinets, fans, spark plugs, and other articles. In the calibration of mass standards, the items dealt with ranged

from microbalance weights to weights used in testing railroad

track scales. The largest operation undertaken was the testing

and evaluation of aircraft scales using 300,000 pounds of accurately

calibrated weights at one time.

4. COOPERATIVE ACTIVITIES

The Bureau's cooperative and consulting activities arise from the

diversity of its program, facilities, and staff in the physical sciences.

These activities range from the development of codes and specifications in cooperation with other groups to active participation

in technical society programs to advisory service for other Government agencies in all areas of the physical sciences.

In the area of codes and specifications the Bureau works largely

as a collaborator and seldom initiates work or promulgates a

finished document. Nevertheless, it often makes a major contribution by providing methods of test, basic scientific and technical

information on properties of materials and related subjects, and

standards of measurement without which no other standards are

possible. Bureau staff members actively participate in national

and international professional societies. This work greatly en- hances the dissemination and utilization of NBS research, development, standardizing, and testing activities. Also, staff members

are able to keep in close touch with technical and scientific advances

132
elsewhere and to coordinate the standards and specifications used

in industry with those employed by Government.

During 1955 staff members participated in the activities of

technical committees of more than 120 national societies, serving

in many cases as chairmen or secretaries. NBS staff members

served as presidents of the International Joint Commission on

Spectroscopy, the Society of Plastics Engineers, the Philosophical

Society of Washington, the Optical Society of America, and the

Instrument Society of America. Numerous directorships and

other positions were held in the major national societies. Internationally, Bureau staff members participated in more than 90

committees of 21 societies, serving as chairmen or secretaries of

approximately 23 committees.

Federal Specifications. The General Services Administration

looks to the Bureau for the preparation or revision of some 175

Federal Specifications. These specifications cover a very wide

range of subjects, practically all fields of science and technology

in which the Bureau has competence. In drawing up a specification, the Bureau is often able to use knowledge gained in research or development work undertaken for other purposes.

Information acquired in the testing of materials purchased by the

Government is also utilized in developing and improving specifications. Because of the magnitude and importance of the Government's purchases of paints and portland cement, research

projects in each of these fields are carried on in close coordination

with the testing operations. In order to find out how well tests of paint work out under practical conditions, the Bureau prepares

and circulates reference samples of paint among a number of

Government laboratories. The results are brought together and

analyzed by the Bureau to find the degree of uncertainty in each

of the tests as it is commonly conducted and to determine which of

the test methods need to be revised in order to improve their

reliability.

In addition to preparing assigned Federal Specifications, the

Bureau is often called upon to review proposed specifications

drafted by others. During the year the General Services Administration submitted more than 450 proposed Federal specifications and amendments to the Bureau for comment. Most of the

comments that were made related to methods of test where the

Bureau had special knowledge or experience.

133
Small high-precision balance on which the Bureau compares standard microbalance weights with standards maintained by the Bureau. Insert: A set of microbalance standard weights; values range from 1 g down to 0.05 mg

(p. 136). Methods of Test. The development of test methods is one of the

statutory functions of the Bureau. In carrying out this function

the aim is to develop general methods that will be applicable to large groups or classes of products—not just individual items.

Among the methods for which the Bureau has accepted responsibility in connection with Federal Specifications are the methods for

adhesives, cements, detergents, laboratory glassware, leather,

paper, plastics, paint, rubber, textiles, and wire and cable. Basic

documents on these methods are customarily issued by the General

Services Administration as Federal Standards. In specifications

for specific products it is only necessary to make appropriate

reference to these standards to provide suitable methods of test. While revisions of test methods are issued only periodically,

continuing work must be done on all of them in order to keep them

in step with the rapid development of modern technology.

Industry Specifications. In order that the Government may

purchase economically, Federal and other Government specifications must be closely coordinated with those of industry and

must take full advantage of new developments and improved

134
manufacturing procedures. The Bureau is enabled to make a

large contribution in this direction through the extensive participation of its staff members in the work of many national standardizing organizations. Currently Bureau staff members hold more than 400 committeeships in the American Society for Testing

Materials, and more than 200 in the American Standards Association.

A new smoothness tester for paper, designed and manufactured

in the United States, has been the subject of a cooperative investigation by NBS and members of the Technical Association of the

Pulp and Paper Industry. The new instrument is being compared

with the present standard in regard to speed and ease of operation,

reproducibility of results, and mandel sensitivity. Under the

direction of the NBS Plastics Section and with the cooperation of

six other laboratories, a revision of the ASTM method for determining the tensile strength of thin plastic films was developed

which has been accepted by ASTM Committee D-20 on Plastics.

Building and Safety Codes. The Bureau assists a variety of

government agencies—State, county, and municipal—in solving

problems relating to building and safety codes. The destructive

storms of the fall of 1954 caused the collapse of a number of radio

and television towers and led to accelerated activity in the revisons

of those portions of codes that relate to wind load on structures. In the building field, cooperative work with representatives of

organizations sponsoring model codes has continued to be effective

in reducing differences in requirements. During 1955 assistance was given in preparing and revising building codes in New Mexico,

New York, and Ohio, as well as in various counties and municipalities throughout the Nation. The Bureau, as either sponsor or cosponsor, assisted in preparing a number of model codes. In

1955 the American Standard Building Code for Masonry was

published by the Bureau, and the American Standard Safety Code

for Elevators was completed. A third code, the American Standard Building Code Requirements for Minimum Design Loads in Buildings, was completed and referred to the American Standards

Association for review. Other model codes in which the Bureau,

as sponsor or cosponsor, has continued to take a leading part, are the National Electrical Safety Code, the Code for the Protection

Against Lightning, and the Code for the Protection of Eyes, Heads,

135
and Respiratory Organs of Industrial Workers. In addition,

members of the staff have taken an active part in preparation or

revision of model codes such as the National Electrical (Fire)

Model Code and the American Standard Model Code for Punch

Presses. Radiation Protection. The National Committee on Radiation

Protection, an advisory group made up of radiation experts and

sponsored by NBS, prepares recommendations for safe operating

and handling procedures for radioactive substances and other

sources of radiation. These are used by industry, the medical

profession, and research workers. At the joint request of the

American College of Radiology, the American Medical Association,

and the U. S. Public Health Service, the Committee several years

ago undertook an intensive study of the problems involved in the

legislative regulation of radiation exposure. The request was prompted by repeated inquiries by individuals and groups seeking

guidance and information on the subject. This study has cul- minated in a report, which is now in press as NBS Handbook 61. This comprehensive report includes a description of the general

problem of developing legislation for the control of radiation exposure, and gives an extended discussion of the various problems

that must be considered by a State in the development of such

legislation. The appendices present (1) a sample law covering the

whole field of radiation protection for use by a State planning such

legislation, and (2) a set of radiation control regulations for use

as a basis for the development of uniform regulations by the States. In addition to this Handbook, three radiation protection reports

have been published during the year and another is in press. Weights and Measures. The translation of the national standards

of length and mass, and of the derived standards of capacity, to the channels of industry and trade is a matter of great economic

importance to the producing, manufacturing, processing, and dis- tributing agencies of this country, and to all purchasers of commodities and services. The individual States have responsibility

for the regulation of commercial weighing and measuring devices.

However, the Bureau cooperates with the States, promoting uniformity in weights and measures laws and methods of inspection

and, by virtue of its custody and maintenance of the national

standards and of its related calibration services, translating the

136
national standards to the channels of trade. To aid in this work,

the Bureau maintains an Office of Weights and Measures.

Commerce and industry have become increasingly aware of the

importance of adequate weights and measures administration. As

a result, greater demands are made upon the Bureau each year

for assistance and advice in this field. The NBS Office of Weights

and Measures, has been conducting a program of assistance to State and local departments, as well as to business and industry,

in the several phases of weights and measures supervision. The

range of consultative services is broad, embracing the drafting of

new legislation, the development of specifications, tolerances, regulations, and testing methods, the design of testing equipment, the

preparation of training films, and the physical adjustment of State

weights and measures standards.

During 1955 the Office of W

T eights and Measures conducted the

40th National Conference on Weights and Measures and planned

and attended regional and State conferences. NBS Handbook 44,

Specifications, Tolerances, and Regulations for Weighing and Measuring Devices, was revised and submitted to the printer. The

report of the 39th National Conference on Weights and Measures was compiled, printed, and distributed. An investigation of

weights and measures approval seals was completed along with

an experiment in farm-milk tank calibration, and a survey on packaged flour and a milk-container study were conducted. Material assistance was rendered to three States toward the development and enactment of extensive weights and measures legislation.

The Bureau during the year released a weights and measures

training film entitled "A True Standard." The film has been

shown at 10 meetings of weights and measures officials, and prints

have been loaned for showing before 60 organizations, including

scientific and professional societies, service clubs, high schools,

colleges and universities, industrial concerns, and law enforcement

agencies of cities, counties, and States. The film has been tele- vised several times. The Bureau has embarked on a new program

of providing essential repairs to basic standards when they are submitted by States for calibration.

Research Associate Program. An important area of cooperation

between the National Bureau of Standards and x^merican industry

is the Bureau's Research Associate Plan. This plan is an arrange137
The substitution method of weighing is recommended for accuratelyfintercomparing test weights with standard weights calibratedjrby the Bureau.

This procedure assures the accurate translation of weight from the Inter- national Standard through the Bureau to the test weights used by State and local inspectors. A new color motion picture on substitution weighing

entitled "A True Standard" was produced by the Bureau. ment whereby technical, industrial, and commercial organizations can support work at NBS on projects which are of special interest

to them, yet of sufficient general interest to justify use of Government facilities. Research associate projects must not only be of value to all groups concerned in the particular field and to the Federal Government, but must also be important from the standpoint of the

Nation's sum total of technologic knowledge. The arrangement

is usually made with an association or group representing a major

part of an industry. However, projects may be undertaken in cooperation with single companies or individuals when the results are expected to be of value to the general public. In any case, the

138
results become a part of the public domain and are published by

the Bureau.

Since the Research Associate Plan was established in 1920,

about 180 organizations and individuals have supported co- operative research at the Bureau. At present 12 groups are supporting some 40 research associates at NBS. Research associate projects active during the past year are as follows:

Sponsor

Aluminum Company of America

American Dental Association American Electroplaters Society

American Iron and Steel Institute American Society for Testing Materials

Asphalt Roofing Industry Bureau Bone Char Research, Inc. Calcium Chloride Association National Research Council

Porcelain Enamel Institute Portland Cement Association

Joint Committee of Chemical Analysis by X-ray Diffraction Methods

(ASTM & Am. Crystallographic

Assoc.)

Field of Activity Reflective thermal insulation Dental research Porosity of electrodeposits

Reinforced concrete Cement reference laboratories Asphalt roofing research Research on adsorbents for sugar refining

Hydration of portland cement Masonry research and fire resistance Test methods for porcelain enamels

Cement research Standard X-ray diffraction powder patterns.

Many of the projects have been specific and therefore of relatively

short duration. Others, such as that supported by the American

Dental Association, have been directed toward fundamental

research in the field; this project has been active since 1928.

Through application of the methods of the physical sciences to the

study of dental materials, the program has aided in the solution of

many of the problems encountered by the practicing dentist, such

as postoperative pain, accurate casting of gold inlays and bridgework, and failure of denture resins.

Optics. The Bureau cooperated in a wide variety of activities

in the field of optics over the past year. At the request of the

Civil Aeronautics Board, the Bureau analyzed the visibility conditions at the time of a mid-air collision at Port Columbus Airport,

Ohio. A meeting on color problems arising in the procurement of

textiles for automobile upholstery was held at the Bureau and was

attended by representatives of the automobile industry, textile

suppliers, and a manufacturer of artificial daylighting equipment.

367607—55 10 139
The Bureau continued its assistance to the Weather Bureau by

calibrating pyrheliometers in the 15-foot light integrating sphere

and assisted the Virginia Highway Department in the calibration

of photometric equipment for highway sign tests. Heat and Power. During the year, the Bureau assisted other

agencies in a consultative capacity on many technical problems

associated with the use or purchase of fuels, lubricants, temperature

measuring devices, antifreezes, and electrical and pneumatic

equipment for aircraft. For example, the Federal Trade Commission was given technical information pertaining to claims made

for automotive products, the Department of Justice was aided in patent litigation, and the Civil Aeronautics Administration

advised regarding the fire hazards of methyl alcohol solutions.

Other work of similar nature included development and revision of

the Federal Standard on Fuels and Lubricants and of specifications

for antifreezes and petroleum ether. Problems where the Bureau

cooperated with national societies include revision of standards for

fuels and lubricants, development of a second standard of viscosity,

and standards for calorimetry. The NBS low-temperature laboratory is cooperating with the Naval Research Laboratory in work on the development of the helium vapor pressure scale of

temperature. Other cooperative work includes active participation in a program of the American Society of Mechanical Engineers

for extending to higher pressures and temperatures the international

tables of thermodynamic and static properties of steam. This

work will aid in the development of more efficient steam turbines

and the rating of steam turbines in international trade.

Building Technology. Government agencies, both in Washington

and elsewhere, consult the Bureau on building construction,

equipment, and practices. Among the recipients of this service

are the Office of the Chief of Army Engineers, the Army Quartermaster Corps, the Navy Bureau of Yards and Docks, the U. S. Coast Guard, the General Services Administration, and the

Federal Housing Administration. For the Department of the

Interior, the Bureau completed a study of the causes of a serious

plaster failure in a hospital in Alaska. Continuing a long-range

understanding, the Bureau this year furnished consultative service on the elevators in the U. S. Capitol, in the new Senate Office

Building, at Carlsbad Caverns in New Mexico, Wind Cave in

140
South Dakota, and at Perry Monument on Lake Erie. Members

of the Bureau staff served as consultants to the Federal Trade

Commission and interested trade organizations in the preparation

of an amendment to the Flammable Fabrics Act. The Bureau

assisted the Atomic Energy Commission in selecting the optimum

concrete for the foundation of the magnet of an alternating gradient

synchrotron at the Brookhaven National Laboratory. At the re- quest of the Smithsonian Institution, a new type of flooring was recommended for use in the National Zoological Park animal cages. The Bureau answered a large number of requests for technical

information on building technology from the general public. These

requests were from home owners, builders, supply dealers, engineering firms, industrial concerns, architects, and educational

institutions. In some cases the information furnished has proved

of considerable benefit to industry. For example, a number of

inquiries were received from insulation manufacturers concerning

the application of reflective surfaces as opposed to other forms of

thermal insulation. The possibilities and advantages of such

insulation have been indicated by work done at the Bureau on

reflectively insulated air spaces. Data Processing. A cooperative program for the Navy Aviation

Supply Office concerned the application of a large-scale generalpurpose electronic digital computer to the task of calculating the

anticipated inventory requirements necessary for the support of

projected aircraft operations throughout the Navy. This was a pioneering step in the development of data-processing techniques

for supply mangement.

In order to provide an integrated information processing system

throughout the supply management organization of the Air Materiel Command, a training course was developed by NBS. The

course provides material and instructions for upper and middle

management personnel. It will train officers from various Air

Materiel Commands to assist in carrying on data-processing programs at their own bases. A training course was also given to Navy supply management personnel on the principles and techniques of automatic data processing for supply management.

Texts, lecture notes, charts, slides, and supplemental reading were

prepared.

141
The Bureau staff participated, along with representatives of

industry and Government, on the Advisory Committee on Application of Machines to Patent Office Operation, and in the preparation of the final report which recommended an extensive program

for mechanizing patent search operations. The Bureau was also

invited to participate in and to give technical information on an

analysis and development program for processing first-class mail

by the Post Office Department. Various aspects of the problem

were considered, particularly mail sorting and handling throughout

the postal system. The ultimate aim is to find the best practical

method for processing first-class mail through the development of

suitable electronic equipment.

Radio Propagation. One of the Bureau's most important services

is its continuous appraisal and advance warning of ionospheric disturbances which disrupt radio communication. Advance forecasts

from 1 to 24 days ahead were continued during the year on a semiweekly basis and medium term forecasts for 24 hours ahead

were made once a day. Short-term forecasts were broadcast from

WWV every 6 hours. Many reports of ionospheric, solar, geomagnetic, and radio wave propagation data were regularly mailed,

telephoned, or telegraphed to Government agencies and commercial

users. Reciprocal ionospheric data were received from 76 national

and international stations. A total of 15 Signal Corps trainees

discussed problems of ionospheric data scaling and processing,

diurnal, seasonal and sunspot cycle trends, and methods of predicting skywave frequencies with members of the staff during

the year. Of particular importance over the past year was planning co- operative work in conjuction with the International Geophysical

Year, 1957-58. Much consultative work has gone into the design

and processing of the new C-4 ionospheric sounder, and of the

airglow photometer for use in connection with these programs.

In addition, the following Technical Panels of the U. S. National

Committee for the International Geophysical Year held meetings

at the Boulder Laboratories during the past year: Ionospheric

Physics, Aurora and Airglow, Cosmic Rays, and Solar Activity.

Several analyses of possible communication via the F2 region were made for the Federal Communications Commission in connection with interference problems. Ratios of expected inter142
An X-ray pattern amplifier demonstrated at the Open House (p. 11) makes

it possible to televise the X-ray image of an operating mechanism. Left: High-energy X-rays from the NBS betatron emerge from a slot in the radia- tion shield and penetrate the test object (a single-cylinder compressor).

The sodium iodide crystal converts the resulting X-ray image into a visual image (right), which is reflected by a mirror to the television camera.

ference were calculated for the International Frequency Bureau

Cochannel Interference Project. An analysis of possible trans- mission for a specified period at 5,966 kilocycles was made for the

Aeronautical Radio, Inc. Representatives of the Signal Corps and Denver Research Insti- tute were advised of the limitations and possibilities of a digital

transmission for television signals. At the request of the Airways

Operations Division of the Civil Aeronautics Administration, esti- mates were made of the service range for ground-wave propagation

at 400 kc and at 215 kc in the vicinity of Point Barrow, Alaska.

A table of ranges for different values of conductivity likely to be

encountered in that area was prepared, based on the CAA's trans- mitting facility of a 40-foot counterpoise antenna with transmitter

power of 400 watts. At the request of the Radio Technical Commission for Marine Services, a study was made of over-water

propagation in the frequency band from 152 to 162 Mc. A report was prepared containing a nomogram from which estimates can

be made of expected service range over salt and fresh water.

Representatives from the Army Electronic Proving Ground,

Fort Huachuca, Arizona, were advised on measurement techniques

for tropospheric scatter propagation programs. Advice was given

representatives of a private firm on techniques for obstacle gain

143
measurements. The FCC was supplied VHF and UHF tropospheric propagation prediction curves and advised on the possibilities of new field-strength measurement techniques.

Approximately 10 industrial concerns inquired concerning the

possibilities of obtaining better standards for frequency. The

State Department, Telecommunications Policy Staff, was assisted

in considerable detail throughout the year in studying and formulating documents for the International Radio Consultative Committee (CCIR) of the International Telecommunication Union.

The Office of the Assistant Secretary of Defense, Advisory Group

on Electronic Parts, was assisted with activities on frequency control devices.

Dental Materials. Since the dental research program is a joint

effort of the Bureau, the Federal Dental Services, and the American

Dental Association, a large part of the research activities are undertaken in order to provide adequate advisory services to these

agencies on the use and procurement of dental materials. Members

of the staff served as official consultants to the Division of Dental

Public Health of the U. S. Public Health Service and the U. S. Naval Dental School. Advice on dental materials and equipment was given to the Interagency Council on Dental Affairs. Lectures on dental research and use of dental materials were given to dentists in the Air Force, Army, and Navy; to students and

faculty of Georgetown Dental School, Howard University Dental

School, and the Medical College of the University of Virginia;

and to 42 miscellaneous groups interested in these materials.

Because of the difficulties encountered by armed services dentists

in the use of improperly stored dental materials as well as materials

of foreign manufacture, a special consulting service has been

established, handled to a large extent by guest workers stationed at NBS by the military services. If the solution to a given problem

cannot be drawn from previous experience, the necessary laboratory

work is carried out to provide the answers. During the past year,

direct assistance was given on the use of impression materials,

duplicating materials, inlay wax, zinc phosphate cements, handpieces, silicate cement, mixing instruments, alginate separating

materials, and partial denture casting techniques.

Metals, Mineral Products, and Other Materials. Fifteen reports were issued to the Civil Aeronautics Board on results of examina144
tion of various failed aircraft parts, such as crankshafts, landing

gears, and engine components, that had caused or contributed to accidents of civilian aircraft. Advice on the failure of a ship propulsion gear was submitted to the Maritime Administration.

Reports were made to the Bureau of Engraving and Printing on the causes and remedies for difficulties encountered in printing presses

that developed wavy and ' 'orange peel" surfaces on transfer plates

and rolls. Metal castings that could not be obtained elsewhere,

because of intricate design, special characteristics, or security

reasons, were made for the Naval Observatory, Naval Gun Factory,

and Diamond Ordnance Fuze Laboratory.

Suggestions, made to the Post Office Department with respect

to properties of the rubber compound used in mail cart tires,

should result in worthwhile savings in maintenance and replacement costs. To prevent corrosion of concrete and metal parts

due to engine fumes in the railroad tunnels under the Chicago

General Post Office, the Bureau advised using plastic panels and

coatings for tunnel linings. Assistance was also given the Post

Office Department in the development of requirements for a reinforced gummed tape. The improved tape permits the use or 2 strips instead of the 6 strips used previously. This method of

sealing is now in the process of adoption for freight shipments.

To eliminate many of the difficulties experienced with plastic

parts in National Security Agency equipment, suggestions were

given as to the types of plastic to be used for particular purposes.

The Corps of Engineers Waterways Experiment Station was given

advice on the use of rubber in coal tar for flexible pavements, and

a research and testing program was suggested which should result

in the savings of several million dollars by guaranteeing a satis- factory pavement in service. As consultant to military agencies

in matters pertaining to optical glass manufacture, specifications,

and testing, the Bureau technically supervised two development

contracts placed with commercial concerns by the Air Force.

Acoustics. The National Institutes of Health need fairly elab- orate records of studies on mentally disturbed persons. These

records include motion pictures and sound recordings of interviews

between patient and physician. Such interviews must be recorded

under the most favorable possible acoustical conditions. The

Bureau advised the Institute on suitable acoustical design of

145
interview rooms. The main feature of the design is adequate

sound insulation against disturbing external noises, but noise

produced in the room itself has also been taken into consideration.

Investigations of the standard for threshold of hearing necessarily require measurements on a large number of persons. Also,

the state of the measuring art is such that careful attention must

be paid to the choice of earphones used for such measurements.

The Bureau advised Walter Reed Army Medical Center on the

number of persons necessary, and the types of earphones required,

in order to yield a useful measurement of the differences between

English and American audiometric thresholds. This required a balance between the number of persons available, the accuracy

necessary to measure the differences, and the rather large inherent

error in making psychoacoustic measurements.

Smog. The Bureau has continued active cooperation with local authorities in California and the Department of Health, Education, and Welfare on the problem of smog. The Bureau contributed original and effective chemical analytical methods fpr determining the constituents of smog. Also, extensive measurements

were made of the distribution of the spectral radiant energy of the sun coming through the smog. It is hoped that analysis of these

data will lead to a better understanding of the source of the smog.

Highway Truck Weighing. The Bureau gave advice to several

groups concerned with the enforcement of State highway laws.

This involved interpreting test results obtained last year on the

weighing of axle loads of motor transport vehicles. The tests showed that the distribution of the total truck weight among the

various axles is constantly changing under road conditions. An

accurate measurement of the truck weight is possible only if all axles are weighed simultaneously. This sort of information is of

considerable importance to State authorities and to the courts who must appraise fairly the claims of truckers. Bureau staff members assisted in the formulation of specifications for foursection motor truck scales under the auspices of the American

Railroad Engineering Association. These specifications are available to all Federal agencies and provide for a much more rigid and

durable installation than the specifications previously offered.

Educational Program. The in-service training opportunities were extended significantly this year by the initiation of a program

146
of postdoctoral research and study and the expansion of the

offerings of the Graduate School to cover a wider segment of the

Bureau's technical and supporting staff. The NBS Boulder

Laboratories, through their Educational Committee, have also

begun a program of graduate studies. Established in 1908, the

Bureau's Graduate School is the oldest in-service training activity

in the Government. The educational program, which has the

cooperation of many universities, provided some 50 courses in the

last year in which approximately 600 staff members participated.

These courses were chosen to improve job efficiency or to prepare

the staff for increased scientific and administrative responsibility

in the near future.

During the past year a program for granting Postdoctoral Research Associateships at the National Bureau of Standards was

announced and implemented. Under this program arranged

jointly by the National Bureau of Standards, the Civil Service

Commission, and the National Research Council-National Academy

of Sciences, a small number of young scientists of exceptional ability

and promise are selected each year for research and study. Selections are made by the National Research Council from a nationwide

competition. Seven Associates were appointed under the program

in the following fields: quantum chemistry, crystal structure,

nuclear physics, physical chemistry, molecular structure and

spectroscopy, mathematics, and statistical mechanics.

In applying for the postdoctoral positions, all applicants sought

close association with particular NBS staff members. Also,

several applicants expressed interest in using some of the Bureau's

unusual equipment, such as the special solenoid for the very precise measurement of electrical quantities and the versatile SEAC

digital computer.

International. The National Bureau of Standards, in exercising

its authorized foreign exchange program and international intercomparison of standards, conducts visitor and training programs

with many foreign scientists. The Bureau annually receives about

1,000 foreign scientific visitors, including technicians sponsored by

many of the Government technical aid and educational exchange

programs. Some of these visitors may spend considerable time in

NBS laboratories as guest workers. These workers and the mem147
A new method for making porcelain jacket crowns was developed under the

research associate plan and the foreign guest worker program. A color motion picture was produced to make the technique available to the dental

profession.

bers of the Bureau staff who visit foreign institutions permit the

Bureau to keep in close touch with scientific developments in other

countries. Services to foreign countries take the form of tests, calibrations, and exchange of standards and publications. Also,

national laboratories of other countries call on the Bureau for advice and assistance on specifications. As an example of the guest

worker program, a foreign scientist working in the dental materials

field has developed a new method of making procelain jacket crowns. A color motion picture film showing the details of the method was

produced and will soon be available for loan to the dental profession throughout the world.

The 50th Jubilee Meeting of the International Electrotechnical

Commission was held in the United States during September 1954.

In addition to participation in its technical sessions, the Bureau,

in cooperation with other local technical groups, planned a 2-day

Washington program for over 200 IEC delegates, including a tour

of NBS laboratories. Other international meetings in which staff members participated were those of the International Commission

on Illumination, International Organization for Standards, Inter- national Union of Pure and x^pplied Physics, International Joint

148
Commission for Spectroscopy, International Union of Pure and

Applied Chemistry, International Commission for Uniform Methods of Sugar Analysis, International Congress for Mathematicians, International Association on Dental Research, the Joint

Commission on Radio Meteorology, International Scientific Radio

Union, International Radio Consultative Committee, International Telecommunications Union, and the International Committee on Weights and Measures.

Members of the staff have been active in international as well as national planning for the International Geophysical Year (page 106),

and in discussions and plans for national and international work of

the International Scientific Radio Union (URSI), the International Radio Consultative Committee (CCIR), the Internationa]

Astronomical Union, and the International Union of Geodesy and

Geophysics. The Xllth General Assembly of URSI will be held

at Boulder, Colorado, in the summer of 1957, with the NBS

Boulder Laboratories serving as one of the host organizations.

5. Appendices

5.1. Organization of the National Bureau of Standards*

Allen V. Astin, Director Associate Director for Chemistry

Wallace R. Brode

Associate Director for Physics

Robert D. Huntoon

Associate Director for Testing

A. T. McPherson

Associate Director for Planning

Nicholas E. Golovin

Assistant Director for Administration R. S. Walleigh

Director Emeritus

Lyman J. Briggs

*As of September 1955.

149
SCIENTIFIC AND TECHNICAL DIVISIONS AND

SECTIONS

ELECTRICITY AND ELECTRONICS

F. B. Silsbee, Chief Resistance and Reactance — J. L. Thomas

Electron Tubes — C. P. Marsden, Jr.

Electrical Instruments — F. M. Defandorf

Magnetic Measurements — I. L. Cooter, Acting

Process Technology — L. P. Tuckerman

Engineering Electronics — G. Shapiro, Acting

Electronic Instrumentation— C. Stansbury

Electrochemistry — W. J. Hamer

OPTICS AND METROLOGY

I. C. Gardner, Chief Photometry and Colorimetry— L. E. Barbrow

Optical Instruments — F. E. Washer

Photographic Technology — R. Davis

Length — L. V. Judson

Engineering Metrology — I. H. Fullmer

HEAT AND POWER

F. G. Brickwedde, Chief Temperature Measurements— J. F. Swindells

Thermodynamics — C. W. Beckett

Cryogenic Physics — R. P. Hudson

Engines and Lubrication — P. M. Ku, Acting

Engine Fuels — F. L. Howard

ATOMIC AND RADIATION PHYSICS

L. S. Taylor, Chief Atomic Physics Laboratory

Spectroscopy —

Radiometry —

Mass Spectrometry —

Solid State Physics —

Electron Physics —

Atomic Physics —

Radiation Physics Laboratory —

Nuclear Physics —

Radioactivity —

X-rays —

Betatron —

Nucleonic Instrumentation —

Radiological Equipment —

Radiation Instruments Branch,

Atomic Energy Commission —

W. F. Meggers

E. K. Plyler

F. L. Mohler

E. K. Plyler, Acting

L. L. Marton

L. M. Branscomb, Acting H. O. Wyckoff

U. Fano

W. B. Mann

H. O. Wyckoff

H. W. Koch

L. Costrell

S. W. Smith

R. L. BUTENHOFF
CHEMISTRY

E. Wichers, Chief Organic Coatings — P. T. Howard

Surface Chemistry — J. I. Hoffman

Organic Chemistry — W. H. Smith

Analytical Chemistry— H. A. Bright

Inorganic Chemistry — R. Gilchrist

Electrodeposition — A. Brenner

Gas Chemistry — E. R. Weaver

Physical Chemistry — E. R. Smith

Thermochemistry — E. J. Prosen

Spectrochemistry — B. F. Scribner

Pure Substances — C. P. Saylor

MECHANICS

W. Ramberg, Chief Sound — R. K. Cook

Mechanical Instruments — E. C. Lloyd

Fluid Mechanics — G. B. Schubau

Engineering Mechanics — B. L. Wilson

Mass and Scale — D. R. Tate

Capacity, Density, and Fluid Meters— H. S. Bean

Combustion Controls — E. F. Fiock

ORGANIC AND FIBROUS MATERIALS

G. M. Kline, Chief Rubber — L. A. Wood

Textiles — W. D. Appel

Paper — R. B. Hobbs

Leather — J. R. Kanagy

Testing and Specifications— R. D. Stiehler

Polymer Structure — N. Bekkedahl

Organic Plastics — F. W. Reinhart

Dental Resarch — W. T. Sweeney

METALLURGY

J. G. Thompson, Chief Thermal Metallurgy — T. G. Digges

Chemical Metallurgy — L. L. Wyman

Mechanical Metallurgy— J, A. Bennett

Corrosion — G. A. Ellinger
MINERAL PRODUCTS

I. C. Schoonover, Chief

Porcelain and Pottery — R. F. Geller

Glass — C. H. Hahner

Refractories — S. Zerfoss

Enameled Metals — W. N. Harrison

Concreting Materials — R. L. Blaine

Constitution and Microstructure— H. F. McMurdie

BUILDING TECHNOLOGY

D. E. Parsons, Chief

Structural Engineering — D. E. Parsons

Fire Protection — A. F. Robertson

Heating and Air Conditioning — R. S. Dill

Floor, Roof, and Wall Coverings— H. R. Snoke

Codes and Specifications — J. A. Dickinson

APPLIED MATHEMATICS

E. W. Cannon, Chief Numerical Analysis -— J. Todd

Computation — M. Abramowitz

Statistical Engineering— C. Eisenhart

Mathematical Physics — R. F. Dressler

DATA PROCESSING SYSTEMS

S. N. Alexander, Chief Components and Techniques —

Digital Circuitry and Devices

Digital Systems —

Analog Systems —

R. D. Elbourn

S. Greenwald {acting) A. L. Liener

H. K. Skramstad {acting)

OFFICE OF PUBLICATIONS

Wallace R. Brode, Chief OFFICE OF WEIGHTS AND MEASURES

W. S. Bussey, Chief OFFICE OF BASIC INSTRUMENTATION

W. A. Wildhack, Chief OFFICE OF TECHNICAL INFORMATION

W. R. Tilley, Chief
ADMINISTRATIVE DIVISIONS

Accounting — P. McClenon

Personnel — G. R. Porter

Administrative Services — H. P. Dalzell

Shops — F. P. Brown

Supply — G. B. Kefover

Management Planning Staff— Ivan Asay

Budget — W. W. Bolton, Jr. Plant — C. A. Dieman

BOULDER LABORATORIES

F. W. Brown, Director CRYOGENIC ENGINEERING

R. B. Scott, Chief Cryogenic Equipment — B. W. Birmingham

Cryogenic Processes — P. C. Vander Arend

Properties of Materials— R. J. Corruccini

Gas Liquefaction — V. J. Johnson

RADIO PROPAGATION PHYSICS

R. J. Slutz, Chief Upper Atmosphere Research — T. N. Gautier

Ionospheric Research (Wash.) — R. Bateman

Regular Propagation Services — W. B. Chadwick

Ionospheric Research (Boulder) — R. C. Ktrbv

RADIO PROPAGATION ENGINEERING

K. A. Norton, Chief Frequency Utilization Research — W. Q. Crichlow

Tropospheric Propagation Research— J. W. Herbstreit

RADIO STANDARDS

H. A. Thomas, Chief High Frequency Standards Branch— W. D. George

Microwave Standards Branch

ADMINISTRATIVE DIVISION— S. W. J. Welch
NATIONAL BUREAU OF STANDARDS

FIELD ESTABLISHMENTS

National Bureau of Standards, Boulder, Colo. Cheyenne Mt. Field Station, Colorado Springs, Colo. Standard Frequency Transmitter WWV, Beltsville, Md.

Standard Frequency Transmitter WWVH, Puuene Maui, T. H.

Radio Field Station, Ft. Belvoir, Va. Radio Propagation Field Station, Sterling, Va. Radio Propagation Field Stations Anchorage, Alaska Puerto Rico

Guam Puuene Maui, T. H.

Narsarssuak, Greenland Gunbarrel Hill, Longmont, Colo. Panama Canal Zone Front Royal, Va.

Point Barrow, Alaska

Lamp Inspector, Brookline 46, Mass. Master Railway Track Scale Depot, Clearing, 111. Materials Testing Laboratores

Allentown, Pa. San Francisco, Calif. Denver, Colo. Seattle, Wash.

5.2. Fiscal Data on NBS Program

PROGRAM AND SOURCE OF FINANCING

Supported by NBS Appropriations

Operating Programs:

Research and Testing

Radio Propagation and Standards

Operation and Administration . . .

Total

Construction and Facilities Programs:

Operation and Administration . . . Construction of Laboratories. . . . .

Total

Total, NBS Appropriations

Supported by Other Agencies

Department of Defense and AEC .... Other Agencies

Total, Other Agencies

Total Program

Obligations Incurred

Fiscal Year 1955

3,207,618

2,088,165

740,000

6,035,783

234,598

304,950

539,548

6,575,331

11,928,000

1,483,100

13,411,100

19,986,431

154
5.3. Advisory Committees

STATUTORY VISITING COMMITTEE

[Reports annually to Secretary of Commerce on NBS activities (Dates indicate expiration of appointment.)] Professor J. H. Van Vleck, Dean, Division of Applied Science, Harvard

University (1956) Dr. M. J. Kelly, President, Bell Telephone Laboratories, Inc. (1957) Dr. Clyde E. Williams, President, Battelle Memorial Institute (1958) Dr. Crawford H. Greenewalt, President, E. I. du Pont de Nemours & Co.

(1959) Dr. Detlev W. Bronk, President, National Academy of Sciences (1960)

NBS TECHNICAL ADVISORY COMMITTEES

[Designated by leading scientific and technical societies to advise NBS Director in specific technical

areas.] AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS

Dr. C. G. Suits, General Electric Company

Dean F. E. Terman, Stanford University Dr. E. W. Engstrom, Radio Corporation of America

Mr. Robert C. Sprague, Sprague Electric Company

Dr. Ralph Bown, Bell Telephone Laboratories Dr. J. A. Hutcheson, Westinghouse Electric Corporation

INSTITUTE OF RADIO ENGINEERS

Dr. A. W. Straiton, University of Texas Dean F. E. Terman, Stanford University

Professor Henry G. Booker, Cornell University

Mr. Harold O. Peterson, Radio Corporation of America

Mr. Stuart L. Bailey, Jansky & Bailey

Dean William L. Everitt, University of Illinois AMERICAN INSTITUTE OF PHYSICS

Professor F. Seitz, University of Illinois Professor D. M. Dennison, University of Michigan Dr. E. M. Purcell, Harvard University

Professor J. A. Bearden, Johns Hopkins University Dr. M. Deutsch, Massachusetts Institute of Technology Dr. Hale Sabine, Celotex Corporation

Professor R. B. Lindsay, Brown University

Dean R. A. Sawyer, University of Michigan

Professor Cecil T. Lane, Yale University

Professor Mark W. Zemansky, City College of New York

Professor A. O. C. Nier, University of Minnesota Dr. L. D. Marinelli, Argonne National Laboratory

POLICY COMMITTEE FOR MATHEMATICS

Dean Mina Rees, Hunter College

Professor Philip M. Morse, Massachusetts Institute of Technology. Dr. Edward Teller, University of California 367607—55 11 155
Professor David Blackwell, Howard University

Professor A. H. Taub, University of Illinois Professor Mark Kac, Cornell University Dr. E. U. Condon, Berkeley, California AMERICAN INSTITUTE OF MINING AND METALLURGICAL

ENGINEERS

Dr. Walter A. Dean, Aluminum Company of America

Mr. Earle E. Schumacher, Bell Telephone Laboratories Dr. Maxwell Gensamer, Columbia University

Mr. Clarence E. Sims, Battelle Memorial Institute Dr. E. C. Smith, Republic Steel Corporation Dr. Cyril S. Smith, University of Chicago

AMERICAN CHEMICAL SOCIETY

Professor N. Howell Furman, Princeton University

Professor C. S. Marvel, University of Illinois Dr. Milton Harris, Harris Research Laboratories Dr. C. F. Rassweiler, Johns Manville Corporation Dr. J. R. Ruhoff, Mallinckrodt Chemical Works

Dr. Norman A. Shepard, Stamford, Conn. Professor Farrington Daniels, University of Wisconsin

AMERICAN CERAMIC SOCIETY

Mr. Ray Birch, Harbison-Walker Refractories Company

Dr. K. C. Lyon, Indiana Glass Company

Mr. E. P. McNamara, Cambridge Tile Company

Dean Elburt Osborn, Pennsylvania State University

Mr. Wayne Deringer, A. 0. Smith Corporation Dr. Allan Bates, Portland Cement Association Dr. A. C. Siefert, Owens-Corning Glass Corporation

Mr. Joe W. Kruson, Big Savage Refractories Corporation

AMERICAN SOCIETY OF MECHANICAL ENGINEERS

Mr. James W. Parker, Ann Arbor, Michigan

Professor Dana Young, Yale University

Professor S. R. Beitler, Ohio State University

Professor C. Harold Berry, Harvard University

Mr. Paul V. Miller, Taft Pierce Manufacturing Company

NATIONAL CONFERENCE ON WEIGHTS AND MEASURES

Mr. John P. McBride, Director of Standards and Necessaries of Life, Boston, Mass. Mr. W. M. Harks, Bowser Inc. Mr. Bruns H. Dreese, Hobart Manufacturing Company

Mr. Alvin V. Hokanson, National Association of Retail Grocers Mr. Charles M. Fuller, Sealer of Weights and Measures, Los Angeles, Cali- fornia Mr. Harry J. Kennedy, Continental Oil Company

Mr. Seth T. Shaw, Safeway Stores, Inc. Mr. C. J. McCaffrey, Ralph N. Brodie Company, Inc. 156
AMERICAN SOCIETY OF CIVIL ENGINEERS

Dr. G. H. Hickox, National Science Foundation Dr. A. T. Ippen, Massachusetts Institute of Technology

Mr. Raymond C. Reese, Toledo, Ohio

AMERICAN STANDARDS ASSOCIATION

Mr. Roger E. Gay, The Bristol Brass Corporation

Mr. John R. Townsend, Sandia Corporation

Mr. Arthur S. Johnson, American Mutual Liability Insurance Company

Vice Admiral G. F. Hussey, Jr., USN (Ret), American Standards Association Mr. Cyril Ainsworth, American Standards Association AMERICAN SOCIETY FOR TESTING MATERIALS

Mr. Norman L. Mochel, Westinghouse Corporation Dr. A. Allan Bates, Portland Cement Association Mr. T. A. Boyd, General Motors Corporation

Mr. Aiken W. Fisher, Fisher Scientific Company

Mr. R. E. Peterson, Westinghouse Research Laboratories

5.4. Awards and Honors

Recognition of the Bureau's contributions to science and technology often takes

the form of awards and honors from academic, industrial, and professional groups. The following list reflects such recognition bestowed on Bureau staff" members

during the fiscal year 1955. RECIPIENT

Bean, Howard S. Bi.andford, Josephine M.

Brode, Dr. Wallace R. Davis, Dr. Philip

Davis, Raymond

Dental Research Section Film, "Hazards of Dental Radiography"

Gardner, Dr. I. C. Gibson, Dr. K. S. Hamer, Dr. W. H., and

Craig, Dr. D. N. Kanagy, Dr. J. R. Norton, K. A. Pafi enbarger, Dr. G. C. (Research Associate, ADA)

Sweeney, W. T. Taylor, L. S. Thompson, G. N. Valore, R. C.

HONOR

Worcester Reed Warner Medal

Certificate of Achievement Honorary Doctor of Science

degree. Awarded Fellowship Awarded Fellowship Awarded Second Place

Frederic Ives Medal

Elected to Fellow

First Prize for Outstanding

Paper, 1954 Awarded $1,000 for Best Paper

on Leather The Stuart Ballantine Award

for 1954

1955 Award of Merit Honorary Membership

Annual Gold Medal Award of Merit Wason Medal

SOURCE

American Society of Mechanical

Engineers

University of Maryland, Alumni

Board of Home Economics Assn. Whitman College, Walla Walla, Wash.

John Simon Guggenheim Memorial

Foundation.

Society of Photographic Engineers.

International Exhibition of Cine- matographic Art in Venice, Italy. Optical Society of America

Illuminating Engineering Society American Institute of Electrical Engineers American Leather Chemists Assn. Franklin Institute Georgetown University School of Dentistry American Dental Assn.

Radiological Society of North

America American Society of Testing Materials American Concrete Institute 157
HONORED BY U. S. DEPARTMENT OF COMMERCE

RECIPIENT

Altman, A. J. Costrell, Louis

Davis, Dr. Marion M.

Gardner, Dr. I. C. Hagaman, Earle M.

Harris, Dr. F. K.

Kiess, Dr. C. C. Marton, Dr. L. L. McIntosh, Jessie H.

Parsons, D. E. Pendergast, W. L. Shartsis, L. Shelton, Dr. G. R. Weissberg, Dr. S. G.

HONOR

Meritorious Service Award

Meritorious Service Award

Meritorious Service Award

Exceptional Service Award

Meritorious Service Award

Meritorious Service Award

Exceptional Service Award

Exceptional Service Award

Meritorious Service Award

Exceptional Service Award

Meritorious Service Award

Meritorious Service Award

Meritorious Service Award

Meritorious Service Award

FIELD OF WORK

Instrument Development

Nucleonic Instrumentation

Physical Chemistry

Optics Photometry & Colorimetry

Electrical Measurements

Spectroscopy

Electron Physics Chemistry Administration

Building Technology

Refractories Research on Glass Ceramics Research Polymer Structure Recognition in the form of Superior Accomplishment Pay Increase Awards

was given 81 Bureau employees. Twenty-three employees were recipients of cash awards for suggestions adopted by the Bureau.

5.5. Publications

Publications in the Bureau's Series Journal of Research. The Journal, issued monthly, presents research papers in various fields of physics, mathematics, chemistry, metallurgy, and the engineering sciences. (Annual subscription: domestic, $4.00; $1.25 additional for foreign

mailing.) Research Papers published from July 1954 to June 1955, inclusive: Volume 53, July—December 1954

2510. Correlation of polarized light phenomena with the orientation of some

metal crystals. C. J. Newton and H. C. Vacher.

2511. Separation of iodide, bromide, and chloride from one another and their subsequent determination. Thomas J. Murphy, W. Stanley Clabaugh, and

Raleigh Gilchrist. 2512. Relative humidity-temperature relationships of some saturated salt solu- tions in the temperature range 0° to 50° C. Arnold Wexler and Saburo

Hasegawa.

2513. Disintegration rate of carbon-14. R. S. Caswell, J. M. Brabant, and A.

Schwebel.

2514. Testing of large optical surfaces with small test plates. James B. Saunders.

2515. Bacher and Goudsmit theory of complex spectra. R. E. Trees.

2516. Self-ignition temperatures of combustible liquids. Nicholas P. Setchkin.

2517. Delta ferrite-austenite reactions and the formation of carbide, sigma, and

chi phases in 18 chromium-8 nickel-3.5 molybdenum steels. H. C. Vacher and

C. J. Bechtoldt.

2518. Determination of hydrogen by slow combustion over platinum in excess oxygen. Shuford Schuhmann and Martin Shepherd.

2519. Anhydrous sodium hydroxide: the heat content from 0° to 700° C, the

transition temperature, and the melting point. Thomas B. Douglas and James

L. Dever.

2520. Heat content of molybdenum disilicide from 0° to 900° C. Thomas

B. Douglas and William M. Logan.

2521. Precise comparison method of testing alternating-current watt-hour meters. A. W. Spinks and T. L. Zapf.

158
2522. Mass spectra of the deuteroethylenes. Vernon H. Dibeler, Fred L. Mohler,

and M. de Hemptinne.

2523. Spectral distribution of energy from the sun. Ralph Stair, Russell G.

Johnston, and Thomas C. Bagg.

2524. Factors affecting the thermal stability of polytetrafluoroethylene. R. E.

Florin, I.. A. Wall, D. W. Brown, L. A. Hymo, and J. D. Michaelsen.

2525. Optical rotations, refractive indices, and densities of dextran solutions. C. F. Snyder, U. S. Isbell, M. R. Dryden, and N. B. Holt.

2526. Calorimetric properties of normal heptane from 0° to 520° K. Thomas

B. Douglas, George T. Furukawa, Robert E. McCoskey, and Anne F. Ball. 2527. Sensitivity—a criterion for the comparison of methods of test. J. Mandel

and R. D. Stiehler. 2528. Infrared emission spectra of cyanide and dicarbon radicals. W. S. Benedict

and Earle K. Plyler. 2529. Refractivity measurements on thick plates. James B. Saunders.

2530. Installation for adiabatic demagnetization experiments at the National Bureau of Standards. D. de Klerk and R. P. Hudson.

2531. Index of refraction of fused-quartz glass for ultraviolet, visible, and infra- red wavelengths. William S. Rodney and Robert J. Spindler. 2532. New experimental designs for paired observations. W. J. Youden and

William S. Connor.

2533. Application of infrared spectroscopy to the determination of impurities in titanium tectrachloride. Rolf B. Johannesen, Charles L. Gordon, James E.

Stewart, and Raleigh Gilchrist. 2534. Some properties of porcelains and phase relations in the ternary systems of

beryllia and zirconia with titania, ceria, and chromia. S. M. Lang, R. S. Roth,

and C. L. Fillmore. 2535. Effects of recent knowledge of atomic constants and of humidity on the

calibrations of the National Bureau of Standards thermal-radiation standards. Ralph Stair and Russell G. Johnston.

2536. Synthesis of D-galactose-l-C 14 and D-talose-l-C 14

. Horace S. Isbell, Harriet

L. Frush, and Nancy B. Holt.

2537. Determination of carbon-14 in solutions of C

14 -labeled materials by means

of a proportional counter. A. Schwebel, H. S. Isbell, and J. D. Moyer.

2538. Extension of the arc spectra of palladium and platinum (6500 to 12000 A). Karl G. Kessler, William F. Meggers, and Charlotte E. Moore.

2539. Influence of molecular shape on the dielectric constant of polar liquids. F. Buckley and A. A. Maryott.

2540. Temperature dependence of compression of linear high polymers at high

pressures. Charles E. Weir.

2541. Turbulent flow in shock tubes of varying cross section. Robert F. Dressier. 2542. Separation of titanium, tungsten, molybdenum, and niobium by anion

exchange. John L. Hague, Eric D. Brown, and Harry A. Bright. 2543. Vapor pressure of nitrogen. George T. Armstrong.

2544. Comparison of four national radium standards. Part 1. Experimental procedures and results. T. I. Davenport, W. B. Mann,

C. C. McCraven, and C. C. Smith. Part 2. Statistical procedures and survey. W. S. Connor and W. J. Youden.

2545. A radiation balance for the macrocalorimetric comparison of four national radium standards. W. B. Mann.

2546. Standard potential of the silver-silver-chloride electrode from 0° to 95° C

and the thermodynamic properties of dilute hydrochloric acid solutions. Roger G. Bates and Vincent E. Bower.

159
2547. The gold-uranium system. R. W. Buzzard and J. J. Park.

2548. A study of absolute standards of mutual inductance and in particular the

three-section National Bureau of Standards type. Frederick W. Grover.

2549. The deuterium-sulfide band at 4,590 cm" 1. Harry C. Allen, Jr., Robert

E. Naylor, and Earle K. Plvler. 2550. Synthesis of a-D-xylose-l-C 14 and /3-D-lyxose-l-C 14

. H. S. Isbell, H. L. Frush, and N. B. Holt.

2551. Creep of high-purity nickel. William D. Jenkins, Thomas G. Digges, Carl R. Johnson.

2552. Determination of nickel, manganese, cobalt, and iron in high-temperature

alloys, using anion-exchange separations. John L. Hague, Edwin E. Maczkowske, and Harry A. Bright. 2553. Thermal degradation of polymers as a function of molecular structure.

S. L. Madorsky and S. Straus. 2554. Some properties of strontium hydroxide and its monohydrate. Eln er T.

Carlson.

2555. Refractivity measurements on Canada balsam by interferometry. James

B. Saunders.

2556. Bounds on a distribution function that are functions of moments to order

four. Marvin Zelen. 2557. Aerological sounding balloons. Gordon M. Martin, John Mandel, and

Robert D. Stiehler. 2558. Plate-separation requirements for standard free-air ionization chambers.

Frank H. Attix and LeRoy DeLaVergne.

Volume 54, January—June 1955

2559. Calibration of meter line standards of length at the National Bureau of Standards. Benjamin L. Page.

2560. Enthalpy and specific heat of four corrosion-resistant alloys at high temperatures. Thomas B. Douglas and James L. Dever.

2561. Effect of temperature on the tensile properties of a commercial and a high

purity 70-percent-nickel—30-percent-copper alloy. William D. Jenkins,

Thomas G. Digges, and Carl R. Johnson.

2562. The system lime-water at 21° C and high pressures. Charles E. Weir.

2563. Absorption of radiant energy by solid particles in suspension. James E.

Stewart.

2564. Branching ratio in the decay of polonium-210. R. W. Hayward, D. D.

Hoppes, and W. B. Mann.

2565. Mechanism of high-speed-waterdrop erosion of methyl methacrylate plastic. Olive G. Engel.

2566. Geometric factors in electrical measurements relating to corrosion and its prevention. W. J. Schwerdtfeger and Irving A. Denison.

2567. Pore-size distribution in collagen and leather by the porosimeter method.

Robert R. Stromberg.

2568. Collagen pores determined by electron microscopy. Max Swerdlow and

Robert R. Stromberg.

2569. Effect of low temperatures on the mechanical properties of a commercially pure titanium. Glenn W. Geil and Nesbit L. Carwile. 2570. Reactions at wet-dry interfaces on fibrous materials. Robert Schaffer, Wm. D. Appel, and Florence H. Forziati. 2571. Scintillation spectrometry of low-energy bremsstrahlung. Margarete

Ehrlich. 2572. A method for the numerical integration of differential equations of second

order without explicit first derivatives. Rene de Vogelaere.

160
2573. Selected positive and negative ions in the mass spectra of the monohalomethanes. Vernon H. Dibeler and Robert M. Reese.

2574. Variation in distortion with magnification. Arthur A. Magill.

2575. Heats of combustion and isomerization of six pentadienes and spiropentane. Frances Maron Fraser and Edward J. Prosen.

2576. Solid-state reactions and dielectric properties in the system magnesialime-tin oxide-titania. L. W. Coughanour, R. S. Roth, S. Marzullo, and F. E.

Sennett.

2577. Chromatographic method for the fractionation of asphalt into distinctive groups of components. Lawrence R. Kleinschmidt.

2578. Nature of stark rubber. Donald E. Roberts and Leo Mandelkern.

2579. Partially balanced incomplete block designs with two associate classes and

two treatments per block. Willard H. Clatworthy.

2580. Solid-state reactions and dielectric properties in the systems magnesiazirconia-titania and lime-zirconia-titania. L. W. Coughanour, R. S. Roth, S. Marzullo, and F. E. Sennett.

2581. Synthesis of a-D-glucose-2-C14

, a-D-mannose-2-C14

, and a-D-galactose-2-C14

. Horace S. Isbell, Harriet L. Frush, and Robert SchafTer. 2582. The system of lime, silica, and water at 180° C. Richard B. Peppier.

2583. An algorithm for solving the transportation problem. A. Gleyzal.

2584. An X-ray study of the system uranium monocarbide-uranium dicarbide- beryllium carbide. M. D. Burdick, H. S. Parker, R. S. Roth, and E. L. McGandy.

2585. An analysis of within-the-hour fading 100- to 1,000-Mc transmissions. H. B. Janes.' 2586. x^stigmatism of skew pencils in optical systems containing toric surfaces. Walter Weinstein.

2587. Osculatory interpolation in the complex plane. Herbert E. Salzer. 2588. Macromethods for reducing aldonic lactones to sugars: the preparation

of L-glucose. Harriet L. Frush and Horace S. Isbell. 2589. Stress-strain relationships in yarn subjected to rapid impact loading:

I. Equipment, testing procedure, and typical results. Walter K. Stone,

Herbert F. Schiefer, and George Fox.

2590. Stress-strain relationships in yarns subjected to rapid impact loading:

2. Breaking velocities, strain energies, and theory neglecting wave propagation.

Frank L. McCrackin, Herbert F. Schiefer, Jack C. Smith, and Walter K. Stone.

2591. Waterdrop collisions with solid surfaces. Olive G. Engel.

2592. 'Effect of Darling-Dennison and Fermi resonance on the thermodynamic

functions. Harold W. Woolley.

2593. Titrations of bases with diphenyl phosphate in some aqueous and non- aqueous solvents. Marion Maclean Davis and Hanna B. Hetzer.

2594. An improved method of measuring efficiencies of ultra-high-frequency and

microwave bolometer mounts. R. W. Beatty and Frank Reggia.

2595. A study of some strontium aluminates and calcium-strontium aluminate

solid solutions. Elmer T. Carlson.

2596. A measurement of the velocity of propagation of very-high-frequency radio waves at the surface of the earth. Edwin F. Florman.

2597. A study of the system magnesium oxide-magnesium chloride-water and the heat of formation of magnesium oxychloride. Edwin S. Newman.

2598. Dielectric relaxation for spherical molecules in a crystalline field: Theory

for two simple models. John D. Hoffman and Benjamin M. Axilrod. Technical News Bulletin. Summaries of current research at the Bureau are published each month in the Technical News Bulletin. Lists of Bureau publications during the preceding month are given. (Annual subscription: domestic,

$1.00; 35 cents additional for foreign mailing.)

161
Basic Radio Propagation Predictions. The Predictions provide the information

necessary for calculating the best frequencies for communication between any two points in the world at any time during the given month. The data are important to all users of long-range radio communications and navigation, in- cluding broadcasting, airline, steamship, and wireless services, as well as to investigators of radio propagation and the ionosphere. Each issue, covering a period of 1 month, is released 3 months in advance and contains 16 pages, including

pertinent charts, drawings, and tables. (Annual subscription: domestic, $1.00; 25 cents additional for foreign mailing.)

Circulars. Compilations of information on various subjects related to the Bureau's scientific and technical activities. Results of Bureau studies and data

of general interest from other sources are included.

539. Volume IV. Standard X-ray Diffraction Powder Patterns. Howard E. Swanson, Ruth K. Fuyat, and George M. Ugrinic.

544. Formulas for Computing Capacitance and Inductance. Chester Snow.

547. Section 1. Precision Laboratory Standards of Mass and Laboratory

Weights. T. W. Lashof and L. B. Macurdy.

548. Miniature Intermediate-Frequency Amplifiers. Robert K-F Seal. 549. Computation of Achromatic Objectives. Robert E. Stephens.

550. Mechanical Failures of Metals in Service. John A. Bennett and Willard

Quick.

551. Computer Development (SEAC and DYSEAC) at the National Bureau of Standards, Washington, D. C.

552. Standard Samples and Reference Standards Issued by the National Bureau

of Standards.

554. Cheyenne Mountain Tropospheric Propagation Experiments. A. P. Barsis,

J. W. Herbstreit, and K. O. Hornberg.

555. Testing of Hydrometers. J. C. Hughes.

556. Thermal Conductivity of Metals and Alloys at Low Temperatures. A Review of the Literature. Robert L. Powell and William A. Blanpied.

558. Bibliography and Index on Dynamic Pressure Measurement. W. G. Brombacher and T. W. Lashof.

559. Specification for Dry Cells and Batteries. 560. Leather Research and Technology at the National Bureau of Standards. Everett L. Wallace.

561. Reference Tables for Thermocouples. Henry Shenker, John I. Lauritzen,

Jr., Robert J. Corruccini, and S. T. Lonberger.

Handbooks. Recommended codes of engineering and industrial practice (in- cluding safety codes) developed in cooperation with interested industries, professional organizations, and regulatory bodies.

54. Protection Against Radiations from Radium, Cobalt-60, and Cesium-137.

57. Photographic Dosimetry of X- and Gamma Rays. Margarete Ehrlich.

58. Radioactive-Waste Disposal in the Ocean.

59. Permissible Dose from External Sources of Ionizing Radiation. Building Materials and Structures Reports. Results of Bureau investigations of building materials and techniques.

141. Fire Endurance of Open-Web Steel-Joist Floors With Concrete Slabs and

Gypsum Ceilings. James V. Ryan and Edward W. Bender.

142. Frost Closure of Roof Vents in Plumbing Systems. Herbert N. Eaton and

Robert S. Wyly.

162
143. Fire Tests of Brick Walls. S. H. Ingberg.

144. Sound Insulation of Wall and Floor Constructions. Applied Mathematics Series. Mathematical tables, manuals, and studies.

32.. Table of Sine and Cosine Integrals for Arguments from 10 to 100.

34. Table of the Gamma Function for Complex Arguments.

37. Tables of Functions and of Zeros of Functions.

39. Contributions to the Solution of Systems of Linear Equations and the Deter- mination of Eigenvalues. Edited by Olga Taussky.

41. Tables of the Error Function and Its Derivative.

42. Experiments in the Computation of Conformal Maps. Edited by John Todd.

43. Tables of Sines and Cosines for Radian Arguments.

44. Table of Salvo Kill Probabilities for Square Targets.

Miscellaneous Publications. Other types of materials, including charts, administrative pamphlets, directories, annual reports ot the Bureau, and conference

reports.

211. American Standard Building Code Requirements for Masonry.

212. Report ot the Thirty-Ninth National Conference on Weights and Measures

1954.

213. Biennial Report 1953 and 1954. National Bureau of Standards.

Publications in Outside Journals

Abramowitz, M., and Antosiewicz, H. A., Coulomb wave functions in the transi- tion region, Phys. Rev. 96, No. 1, 75 (Oct. 1954). Abramowitz, M., and Rabinowitz, P., Evaluation of Coulomb wave functions along the transition line, Phys. Rev. 96, No. 1, 77 (Oct. 1954). Achenbach, P. R., and Phillips, C, Water demand rates for electric drinking- water coolers of the bubbler type, Refrig. Eng. 37 (Dec. 1954). Agy, V., Geographic and temporal distribution of Polar blackouts, J. Geophys.

Research 59, No. 4, 499 (1954).

Allen, H. C, Tidwell, E. D., and Plyler, E. K., Vibrational energy of aleuterium

cyanide, J. Chem. Phys. 23, 1356 (1955). Ambler, E., Hudson, R. P., and Temmer, G. M., Alignment of cerium141 and

neodynium147

, Phys. Rev. 97, 1212 (1955). Ambler, E., and Hudson, R. P., Critical field phenomena in an isotropic para- magnetic crystal, Phys. Rev. 96, No. 4, 907 (Nov. 1954). Ambler, E., and Hudson, R. P., Measurements of chromium potassium alum

below 1° K, Phys. Rev. 95, 1143 (1954). Antosiewicz, H. A., and Abramowitz, M., A representation tor solutions of

analytic systems of linear differential equations, J. Wash. Acad. Sci. 44,

No. 12, 383 (Dec. 1954). Antosiewicz, H. A., and Davis, P., some implications of Liapunov's conditions for

stability, J. Rational Mechanics and Analysis 3, No. 4, 447 (1954). Antosiewicz, H., and Hoffman, A., A remark on the smoothing problem, Management Sci. 1, No. 1, 92 (Oct. 1954). Appel, W. D., Synthetic textiles, Encyclopedia Americana (1955). Appel, W. D., Internationa] methods tor testing colorfastness of textiles, Mag. ot Standards 26, 44 (Feb. 1955).

Attix, F. H., and DeLaVergne, L., Plate separation requirements tor standard

free-air ionization chambers, Radiology 63, No. 6, 853 (Dec. 1954). 163
Bailey, D. K., Scattering at oblique incidence from ionospheric irregularities,

The Physics of the Ionosphere, 1954 Cambridge Conference Report, p. 99. Barghausen, A. F., Decker, M. T., and Maloney, L. J., Measurements of

correlation, height gain, and path antenna gain at 1046 Mc on spaced antennas

far beyond the radio horizon, IRE Convention Record (1955). Bates, R. G., Chemical education in Switzerland, The Capital Chemist 4, No. 5, 150 (1954). Bates, R. G., and Schwarzenbach, G., Triathanolamin als puffersubstanz, Helv. Chim. Acta 37, 1439 (1954). Bates, R. G., and Schwarzenbach, G., Note on the strength of picric acid, Experientia 10, 482 (1954). Bates, R. G., and Schwarzenbach, G., Uber pH-Werte nichtwasseriger, Losungen,

Helv. Chim. Acta 38, 699 (1955). Bates, R. G., and Schwarzenbach, G., Eie bestimmung thermodynamischer

aciditatskonstanten, Helv. Chim. Acta 37, 1069 (1954). Bean, H. S., A pound of gas? Gas 30, No. 12, 31 (Dec. 1954). Bean, L., and Hackney, E. J., A study of some operations involved in cement

analysis, ASTM Bull. No. 197, 43 (1954). Bean, L., and Tucker, N. J., A note on the oxyquinolate determination of magnesi- um oxide in cement, ASTM Bull. (TP224) No. 201, 62 (Oct. 1954). Bean, R. B., Prolonged space-wave fadeouts at 1,046 Mc observed in Cheyenne

Mountain propagation program, Proc. IRE 42, No. 5, 848 (1954). Becker, J

. H., Studies of crystal growth, and electrical and optical properties of gray tin, Phvs. Rev. 98, 1192A (1955). Bekkedahl, N. P., and Tryon, M., Biennial review of physical and chemical test methods on natural and synthetic rubber, Anal. Chem. 27, 589 (Apr. 1955). Bellman, R., and Hoffman, A., On a theorem of Ostrowski and Taussky, Archiv

Der Mathematik 5, 123 (1954). Berger, M., Montecarlo calculations of y-ray backscattering and transmission,

Radiation Research 1, No. 5, 489 (Oct. 1954). Bestul, A. B., Composition of apparent shearing forces during shear degradation

of polymers, J. Appl. Phys. 25, 1069 (1954).

Biagi, F., and Cook, R. K., Acoustic impedance of a right circular cylindrical

enclosure, J. Acoust. Soc. Amer. 26, No. 4, 506 (July 1954). Birnbaum, G., and Maryott, A. A., Temperature dependence of the microwave

absorption of NH3 , J. Chem. Phys. 22, No. 8 (Aug. 1954). Birnbaum, G., Maryott, A. A., and Wacker, P. F., Microwave absorption bv the nonpolar gas C02; J. Chem. Phys. 22, No. 10 (Oct. 1954). Blanch, G., On modified divided differences I, Math. Tables and Other Aids to Computation 8, No. 45, 1 (1954). Blanch, G., and Rhodes, I., Tables of characteristic values of Mathieu's equation

for large values of the parameter, J. Wash. Acad. Sci. 45, 166 (June 1955). Blunt, R. F., Frederikse, H. P. R., Becker, J. H., and Hosier, W. R., Electrical and optical properties of intermetallic compounds. Ill, Aluminum antimonide,

Phys. Rev. 96, 578 (1954). Blunt, R. F., Frederikse, H. P. R., Hosier, W. R., Properties of Mg2 Sn, Phys. Rev. 98, 1533A (1955). Blunt, R. F., Hosier, W. R., and Frederikse, H. P. R., Electrical and optical

properties of intermetallic compounds. II. Gallium antimonide, Phys. Rev.

96, 576 (1954). Boag, J. W., The distribution of linear energy transfer, or "ion density" for fast neutrons in water, Radiation Research 1, No. 4, 323 (1954). Boag, J., and Zendle, B., Scattered radiation contribution to depth dose data for 35-Mev and 90-Mev synchrotron X-rays, Phys. Rev. 95, 608A (1954).

164
Boggs, G. E., Gain stable mixers and amplifiers with current feedback, Proc. IRE 42 No. 7, 1145 (July 1954). Bogue, R. H., Cement, Encyclopedia Americana 6, 188; PCAF Paper No. 68

(1955). Bogue, R. H., The calcium silicate hydrates, Proc. International Congress of

Industrial Chem.; PCAF Paper No. 69 (1954). Bradt, P., and Mohler, F. L., Analysis of fluorinated polyphenyls by mass spec- trometer, Anal. Chem. 27 875 (1955). Branscomb, L. M., and Smith, S. J., Electron affinity of atomic oxygen, Phys. Rev. 98, 1127L (1955). Branscomb, L. M., and Smith, S. J., Experimental cross section for photodetachment of electrons from H' and D", Phys. Rev. 98 1028 (1955). Brauer, G. M., and Sweeney, W. T., Effect of temperature and degree of poly- merization on the sorption of water bv polymethyl methacrylate, Modern

Plastics 32, 138 (May 1955). Breckenridge, R. G., Blunt, R. F., Hosier, W. R., Frederikse, H. P. R., Becker

J. H., and Oshinsky, W., Electrical and optical properties of intermetallic compounds. I. Indium antimonide, Phys. Rev. 96 571 (1954). Brenner, A., Electroless plating comes of age, Metal Finishing 52, No. 11, 68; No. 12, 61 (1954). Brickwedde, F. G., Giauque-Kelving proposal, Phys. Today 7 4 (1954). Brickwedde, F. G., Low temperature physics, J. Am. Chem. Soc. 76 2030 (1954).

Brode, W. R., Seldin, I. L., Spoerri, P. E., and Wyman, G. M., The relation between the absorption spectra and the chemical constitution of dyes.

XXVIII The hydration of Azo dyes in organic solvents, J. Am. Chem. Soc. 77

2762 (1955). Broida, H. P., and Gaydon, A. G.,The Herzberg bands of O

2 in an oxygen after- glow and in the night sky spectrum, Proc. Roy. Soc, Series A. 222 181 (1954). Broida, H. P., and Kostkowski, H. J., Experimental evidence for the existance of abnormal OH rotational "temperatures" in low pressure flames, J. Chem. Phys.

23, 754 (1955). Broida, H. P., and Morowitz, H. J., Flames, Sci. Monthly 80, No. 1, 3 (Jan. 1955).

Broida, H. P., and Pellam, J. R., A note on the preparation of solid ozone and

atomic oxygen, J. Chem. Phys. 23, 409 (1955). Broida, H. P., and Pellam, J. R., Phosphorescence of atoms and molecules of

solid nitrogen at 4.2° K, Phys. Rev. 95, No. 3, 845 (Aug. 1954). Brvsk, H., Spatial distribution of energy dissipation by high-energy X-rays, Phys. Rev. 96, No. 2, 419 (Oct. 1594). Burkhard, M. D., and Corliss, E. L. R., The response of earphones in ears and

couplers, J. Acoust. Soc. Amer. 26, No. 5, 679 (Sept. 1954). Cameron, J. M., and Ogburn, F., Acceptance sampling of electroplated articles, Plating 41, No. 1, 43 (1954). Carl, H. F., Jaffe, H. W., and Hockman, A., New techniques for evaluating natural corundum ores, Mining Eng. 6, No. 4, 402 (1954). Carpenter, F. G., A review of pressure drop across columns of bone char, Intern. Sugar J. 57, 12 (Jan. 1955). Cleek, G. W., and Hamilton, E. H., The development of some infrared transmiting glasses, Proc. of the Conference of Infrared Optical Materials, Filter and

Films; Eng. Res. and Dev. Laboratories; The Eng. Ctr. Fort Belvoir, Virginia;

p. 1 (1954). Conrad, G. T., Noise measurements of composition resistors, Electronics Conf. Yearbook (1954).

Costrell, L., Precision 5-10 kv high-voltage supply. Nucleonics 13, No. 3, 63

(1955).

165
Crandall, J. R., Observations on field exposures of enameled ranges. Proc. of the Porcelain Enamel Institute Forum 16, 27 (Sept. 1954). Dahl, S., Effect of sample preparation on precision in the hide substance determination, J. Am. Leather Chemists' Assoc. 49, 515 (July 1954). Davis, J. H., and Oehler, R., Method for restoring original appearance of impregnated leather, J. Am. Leather Chemists' Assoc. 50, 38 (Jan. 1955). Davis, M. M., and Hetzer, H. B., The relative basicities of tribenzylamine and

tribenzylamine oxide in benzene and water. J. Am. Chem. Soc. 76, 4247

(1954). Davis, P., Linear functional equations and interpolation series, Pac. J. Math. 4, No. 4, 503 (Dec. 1954). Davis, P., and Pollak, H., Complex biorthogonality for certain sets of polynomials,

Duke Math. J. 21, No. 4, 653 (Dec. 1954). Davis, P., and Rabinowitz, P., On the estimation of quadrature errors for analytic

functions, Math. Tables and Other Aids to Computation 8, No. 48, 194 (Oct. 1954).

Davis, P., and Walsh, J. L., On representations and extension of bounded linear functionals defined on classes of analytic functions, Trans. Amer. Math. Soc. 76, No. 2, 190 (1954). DeWane, H. J., Standard test for photofksh cells, Standards 26, No. 5 (May 1955). Diamond, J. J., Flame photometric determination of strontium in portland cement,

Anal. Chem. 27, 913 (June 1955).

Dill, R. S., American Society of Heating and Ventilating Engineers Research,

The Heating, Piping and Air Conditioning Mag. 171 (March 1955). Diniak, A. W., Hughes, E. E., and Fujii, M., Determination of water content in Freon-12 circulating in a refrigeration system, Refrig. Eng. 62, No. 2, 56 (1954). Dougherty, H. T., The propagation characteristics of the frequency band 152-162

Mc which is available for Marine radio communications, Appendix E to study

of a reliable short-range radio telephone system, Report of Special Committee

No. 19, Radio Tech. Comm. for Marine Serv., Washington, D. C. Douglas, T. B., and Dever, J. L., Heat content of lead from 0° to 900° and the heat of fusion, J. Am. Chem. Soc. 76, 4824 (1954). Douglas, T. B., and Dever, J. L., Lithium fluoride; Heat content from 0° to 900°, the melting point and heat of fusion, J. Am. Chem. Soc. 76, 4826 (1954). Eubanks, A. G., Richmond, J. C, and Moore, D. G., Studies of oxidation behavior of enameling iron during firing, Finish 11, No. 5, 50 (1954). Fan, K., Taussky, O., and Todd, J., Discrete analogs of inequalities of Wirtinger.

Monatsh. Math. 59, 73 (1955). Fano, U., A similarity principle in the backscattering of 7-rays. Radiation

Research, 1, No. 5, 495 (Oct. 1954). Feinstein, J., Information theory aspects of propagation through time-varying

media, J. Appl. Phys. 26, 2, 219 (Feb. 1955). Forsythe, G. E., Asymptotic lower bounds for the frequencies of certain polygonal membranes, Pac. J. Math. 4, No. 2, 467 (Sept. 2954).

Fred, M., Tomkins, F. S., Meggers, W. F., Nuclear moments of Ac227

, Phys. Rev. 98, 1514 (1955).

Friedman, A. S., and Haar, L., High-speed machine computation of ideal gas thermodynamic functions. I. The isotopic water molecules, J. Chem. Phys.

22, 2051 (1954). Friedman, A. S., Trzeciak, M., and Johnston, H. L., Pressure-volume temperature

relations of liquid normal deuterium, J. Am. Chem. Soc. 76, 1552 (1954).

Fuller, E. G., Photodisintegration of helium 4, Phys. Rev. 96, 1306 (1954). Gautier, W. K., Meteorological instrumentation at the National Bureau or Standards, Weatherwise 7, No. 4, 86 (1954).

166
Gee, A., Domingues, L. P., and Deitz, V. R., Determination of inorganic constitu- ents in sucrose solutions, Anal. Chem. 26, 1487 (1954). Gee, A., and Deitz, V. R., Pyrophosphate formation upon ignition of precipitated

basic calcium phosphates, J. Am. Chem. Soc. 77, 2961 (1955). Gerjuoy, E., and Saxon, D. S., Variational principles for the acoustic field, Phys. Rev. 94, No. 6, 1445 (1954).

' Giles, J. R., Observations in abrasion testing, Proc. Porcelain Enamel Institute Forum, 16, 136 (Sept. 1954). Glasgow, A. R., and Ross, G. S., Improved stainless steel needle valve, Anal. Chem. 26, 2003 (Dec. 1954).

Haar, L., and Friedman, A. S., High-speed computation of ideal gas thermodynamic functions. II. The diatomic free radicals of the isotopic hydrides of oxygen and sulphur, J. Chem. Phys. 23, 869 (1955). Haas, P. H., Harrington, R. D., Powell, R. C, and Rasmussen, A. L., Instrument

for magnetic high frequency measurements, Wright Air Development Ctr., Tech. Report 54-238 (1954). Haliday, W. G., and Nail, J. R., Drain casting of a high-grade magnesium oxide support used in an experimental vacuum tube, Rev. Sci. Instr. 25, No. 12, 1225

(Dec. 1954). Hansen, W. B., and Pellam, J. R., Second sound attenuation in liquid helium II. Phys. Rev. 95, 321 (1954). Hart, V. E., A semi-micro dilution viscometer, J. Polymer Sci. 17, 207 (June 1955). Hart, V. E., A graphical method for single-point determination of intrinsic vis- cosity, J. Polymer Sci. 17, 215 (June 1955).

Hartsfield, W. L., Observations of distant meteor-trail echoes followed by ground

scatter, J. Geophys. Research 60, 1, 53 (Mar. 1955).

Hawkins, J. E., and Armstrong, G. T., The physical properties of terpenes. III. The vapor pressures of alpha pinene and beta pinene, J. Am. Chem. Soc. 76,

3756 (1954). Hayward, E., and Fuller, E. G., Nuclear elastic scattering of photons, Phys. Rev. 95, 1106L (1954). Hayward, R. W., and Hoppes, D. D., Inner bremsstrahlung from V

49

, Bull. Am.

Phys. Soc. 30, No. 3, 59A (1955). Hayward, R. W., and Hoppes, D. D., Disintegration of selenium-73, Bull. Am.

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